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Yan L, Shi J, Zhu J. Cellular and molecular events in colorectal cancer: biological mechanisms, cell death pathways, drug resistance and signalling network interactions. Discov Oncol 2024; 15:294. [PMID: 39031216 DOI: 10.1007/s12672-024-01163-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Accepted: 07/15/2024] [Indexed: 07/22/2024] Open
Abstract
Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide, affecting millions each year. It emerges from the colon or rectum, parts of the digestive system, and is closely linked to both genetic and environmental factors. In CRC, genetic mutations such as APC, KRAS, and TP53, along with epigenetic changes like DNA methylation and histone modifications, play crucial roles in tumor development and treatment responses. This paper delves into the complex biological underpinnings of CRC, highlighting the pivotal roles of genetic alterations, cell death pathways, and the intricate network of signaling interactions that contribute to the disease's progression. It explores the dysregulation of apoptosis, autophagy, and other cell death mechanisms, underscoring the aberrant activation of these pathways in CRC. Additionally, the paper examines how mutations in key molecular pathways, including Wnt, EGFR/MAPK, and PI3K, fuel CRC development, and how these alterations can serve as both diagnostic and prognostic markers. The dual function of autophagy in CRC, acting as a tumor suppressor or promoter depending on the context, is also scrutinized. Through a comprehensive analysis of cellular and molecular events, this research aims to deepen our understanding of CRC and pave the way for more effective diagnostics, prognostics, and therapeutic strategies.
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Affiliation(s)
- Lei Yan
- Medical Department, The Central Hospital of Shaoyang Affiliated to University of South China, Shaoyang, China
| | - Jia Shi
- Department of Obstetrics and Gynecology, The Central Hospital of Shaoyang Affiliated to University of South China, Shaoyang, China
| | - Jiazuo Zhu
- Department of Oncology, Xuancheng City Central Hospital, No. 117 Tong Road, Xuancheng, Anhui, China.
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2
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Takao M, Yamaguchi T, Eguchi H, Suzuki O, Mori Y, Chika N, Yamada T, Okazaki Y, Tomita N, Nomizu T, Momma T, Takayama T, Tanakaya K, Akagi K, Tanabe N, Ishida H. Predictive modeling for the germline pathogenic variant of the APC gene in patients with adenomatous polyposis: proposing a new APC score. Surg Today 2024:10.1007/s00595-024-02894-y. [PMID: 38970662 DOI: 10.1007/s00595-024-02894-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 06/23/2024] [Indexed: 07/08/2024]
Abstract
BACKGROUND The precise diagnosis and medical management of patients with suspected familial adenomatous polyposis should be based on genetic testing, which may not always be available. Therefore, establishing a new model for predicting the likelihood of a germline pathogenic variant (GPV) of APC based on its clinical manifestations could prove to be useful in clinical practice. METHODS The presence of GPVs of APC gene was investigated in 162 patients with adenomatous polyposis (≥ 10 polyps) using a multigene panel or single-gene testing. To generate a predictive model for GPV of the APC gene, a logistic regression analysis was performed using the clinicopathological variables available at the time of the diagnosis of adenomatous polyposis. RESULTS Ninety (55.6%) patients had GPV of the APC gene. According to a multivariate logistic regression analysis, age < 40 years, polyps ≥ 100, fundic gland polyposis, and a family history of colorectal polyposis were found to be independent predictors of the GPV of APC and were used to establish a formula for predicting the GPV of APC using the four predictors. The prediction model had an area under the curve of 0.91 (0.86-0.96) according to a receiver operating characteristic analysis. CONCLUSION The model for predicting the GPV of APC will help patients with adenomatous polyposis and physicians make decisions about genetic testing.
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Affiliation(s)
- Misato Takao
- Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan
| | - Tatsuro Yamaguchi
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
- Department of Clinical Genetics, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-Ku, Tokyo, 113-8677, Japan.
| | - Hidetaka Eguchi
- Diagnostics and Therapeutics of Intractable Diseases and Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Okihide Suzuki
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Yoshiko Mori
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Noriyasu Chika
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Takeshi Yamada
- Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Tokyo, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases and Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Naohiro Tomita
- Division of Lower GI Surgery, Department of Surgery, Hyogo College of Medicine, Hyogo, Japan
| | - Tadashi Nomizu
- Department of Surgery, Hoshi General Hospital, Fukushima, Japan
| | - Tomoyuki Momma
- Department of Gastrointestinal Tract Surgery, Fukushima Medical University, Fukushima, Japan
| | - Tetsuji Takayama
- Department of Gastroenterology and Oncology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Kohji Tanakaya
- Department of Surgery, NHO Iwakuni Clinical Center, Yamaguchi, Japan
| | - Kiwamu Akagi
- Division of Molecular Diagnosis and Cancer Prevention, Saitama Cancer Center, Saitama, Japan
| | - Noriko Tanabe
- Department of Genomic Medicine, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Hideyuki Ishida
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
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3
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Sutherland RL, Boyne DJ, Brenner DR, Cheung WY. The Impact of BRAF Mutation Status on Survival Outcomes and Treatment Patterns among Metastatic Colorectal Cancer Patients in Alberta, Canada. Cancers (Basel) 2023; 15:5748. [PMID: 38136294 PMCID: PMC10741517 DOI: 10.3390/cancers15245748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/27/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
Colorectal cancer presents via multiple different clinical phenotypes that can arise from a variety of different genetic and molecular alterations. The aim of this study was to describe survival outcomes and treatment patterns of metastatic colorectal cancer (mCRC) patients by v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation status. The Alberta Cancer Registry was used to identify all patients >18 years old who had been diagnosed with mCRC in Alberta between 1 January 2017 and 31 December 2019 and had received at least one cycle of systemic therapy. Treatment patterns were compared between wild-type and mutant BRAF mCRC patients. Cox regression models and Kaplan-Meier curves were created to assess survival differences by both treatment pattern and BRAF status. A total of 488 patients were identified with mCRC, of which 42 (11.4%) were confirmed to have a BRAF mutation. The most common first-line treatment regimen was either capecitabine and oxaliplatin (CAPOX) or leucovorin calcium (folinic acid), fluorouracil, and oxaliplatin (FOLFOX). The median overall survival for mCRC patients was 20.01 months. Mutant BRAF patients had a median survival of 8.21 months compared to 20.03 months among those with wild-type BRAF. BRAF mutations among mCRC patients are associated with a considerably poor prognosis, reinforcing the need for clinical BRAF testing among newly diagnosed patients to better understand their prognosis.
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Affiliation(s)
- R. Liam Sutherland
- Department of Community Health Sciences, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Devon J. Boyne
- Department of Oncology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Darren R. Brenner
- Department of Community Health Sciences, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Oncology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Winson Y. Cheung
- Department of Community Health Sciences, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Oncology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
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Wang K, Zou B, Chen F, Zhang J, Huang Z, Shu S. Case report: Three novel variants on SLC25A13 in four infants with neonatal intrahepatic cholestasis caused by citrin deficiency. Front Pediatr 2023; 11:1103877. [PMID: 37063661 PMCID: PMC10090684 DOI: 10.3389/fped.2023.1103877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/09/2023] [Indexed: 04/18/2023] Open
Abstract
Background Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a common clinical phenotype of citrin deficiency in infants. Its phenotype is atypical, so genetic testing is quite necessary for the diagnosis. Case presentation We report 4 patients with jaundice and low body weight. Furthermore, the biochemical examination of all showed abnormal liver function and metabolic changes. DNA samples of the patients were extracted and subjected to genetic screening. All candidate pathogenic variants were validated by Sanger sequencing, and CNVs were ascertained by qPCR. The genetic screening revealed 6 variants in 4 patients, and all patients carried compound heterozygous variants of SLC25A13. Importantly, 3 variants were newly discovered: a nonsense mutation in exon17 (c.1803C > G), a frameshift mutation in exon 11(c.1141delG) and a deletion of the whole exon11. Thus, four NICCD patients were clearly caused by variants of SLC25A13. Biochemical indicators of all patients gradually returned to normal after dietary adjustment. Conclusions Our study clarified the genetic etiology of the four infants, expanded the variant spectrum of SLC25A13, and provided a basis for genetic counseling of the family. Early diagnosis and intervention should be given to patients with NICCD.
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Wang Y, Li S, Wu D, Yan H. Title: Noninvasive prenatal testing of hereditary colorectal cancer syndromes using cell-free DNA in maternal plasma. Prenat Diagn 2022; 42:557-566. [PMID: 35343616 DOI: 10.1002/pd.6137] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVE This study aimed to establish a practical protocol for early noninvasive prenatal testing (NIPT) for fetuses at risk of Peutz-Jeghers syndrome (PJS) or familial adenomatous polyposis (FAP), two classical types of hereditary colorectal cancer syndromes, for risk evaluation and whole-life monitoring. METHOD Target enrichment was performed using hybridization probes coordinating the STK11 gene region and APC gene region, with 1,458 highly heterozygous SNPs included. Semitarget amplification random sequencing was used for large fragment deletion detection. For relative haplotype dosage (RHDO) analysis, haplotype construction was performed by SHAPEIT software, the CBS algorithm was used for recombination event calculation, and Bayes factor was used for the determination of whether the fetus was affected. RESULTS Haplotypes were successfully constructed in the nine recruited families with different pedigree characteristics, and the results for the RHDO analysis were consistent with the amniocentesis sampling detection results. The cell-free fetal DNA fraction can be detected as low as 2% in maternal plasma. CONCLUSION This is the first NIPT assay on hereditary colorectal cancer syndromes based upon RHDO analysis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yao Wang
- Center for Reproductive Medicine, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Suqing Li
- Celula Medical Technology Co., Ltd. Chengdu, Chengdu, China
| | - Di Wu
- Celula Medical Technology Co., Ltd. Chengdu, Chengdu, China
| | - Hongli Yan
- Center for Reproductive Medicine, Changhai Hospital, Naval Medical University, Shanghai, China
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Lee JK, Kwon WK, Hong SN, Chang DK, Kim HC, Jang JH, Kim JW. Necessity of Multiplex Ligation Probe Amplification in Genetic Tests: Germline variant analysis of the APC gene in familial adenomatous polyposis patients. Cancer Genet 2022; 262-263:95-101. [DOI: 10.1016/j.cancergen.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 01/10/2022] [Accepted: 02/09/2022] [Indexed: 11/02/2022]
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Takao M, Yamaguchi T, Eguchi H, Yamada T, Okazaki Y, Tomita N, Nomizu T, Momma T, Takayama T, Tanakaya K, Akagi K, Ishida H. APC germline variant analysis in the adenomatous polyposis phenotype in Japanese patients. Int J Clin Oncol 2021; 26:1661-1670. [PMID: 34106356 DOI: 10.1007/s10147-021-01946-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 05/25/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Familial adenomatous polyposis (FAP), an autosomal dominant disorder characterized by multiple colonic polyps, is caused by a germline pathogenic variant of the APC gene. However, this variant is not detected in up to 30% of patients with the adenomatous polyposis phenotype. METHODS We performed next-generation sequencing (NGS) to identify the causative genes in FAP patients with 10 or more polyps. For patients in whom the APC germline variant was not able to be identified, we screened for APC mosaicism using high-coverage NGS of APC with DNA from leucocytes and/or frozen tissue. RESULTS The pathogenic APC germline variant was found in 93.3%, 71.6%, and 17.1% of patients with profuse-type polyposis, sparse-type polyposis, and oligo-polyposis, respectively. The APC germline variant detection rate in patients with FAP-related diseases was 69.7% for fundic gland polyposis, 79.7% for duodenal adenoma, 94.7% for desmoid tumor, and 71.4% for thyroid cancer, with increasing numbers of extracolonic lesions associated with an increasing APC germline variant detection rate. A mosaic test detected nine patients with APC mosaicism. A comparison of APC-associated polyposis with APC mosaicism showed that patients with APC mosaicism had a low frequency of duodenal adenoma and a family history of colonic polyposis. CONCLUSIONS We determined the detection rate of the APC germline variant by phenotype and identified APC mosaicism. Genetic testing of FAP patients is important because it can help with surgical decision-making, monitoring, and genetic counseling. Furthermore, genetic testing by NGS proved to be an effective method of detecting APC germline variants.
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Affiliation(s)
- Misato Takao
- Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, 3-18-22, Honkomagome, Bunkyo-ku, Tokyo, 113-8677, Japan.,Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Tatsuro Yamaguchi
- Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, 3-18-22, Honkomagome, Bunkyo-ku, Tokyo, 113-8677, Japan. .,Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan. .,Department of Clinical Genetics, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan.
| | - Hidetaka Eguchi
- Diagnostics and Therapeutics of Intractable Diseases and Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takeshi Yamada
- Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Tokyo, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases and Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Naohiro Tomita
- Division of Lower GI Surgery, Department of Surgery, Hyogo College of Medicine, Nishinomiya, Japan
| | - Tadashi Nomizu
- Department of Surgery, Hoshi General Hospital, Koriyama, Japan
| | - Tomoyuki Momma
- Department of Gastrointestinal Tract Surgery, Fukushima Medical University, Fukushima, Japan
| | - Tetsuji Takayama
- Department of Gastroenterology and Oncology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kohji Tanakaya
- Department of Surgery, Iwakuni Clinical Center, Iwakuni, Japan
| | - Kiwamu Akagi
- Division of Molecular Diagnosis and Cancer Prevention, Saitama Cancer Center, Saitama, Japan
| | - Hideyuki Ishida
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
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Hull R, Francies FZ, Oyomno M, Dlamini Z. Colorectal Cancer Genetics, Incidence and Risk Factors: In Search for Targeted Therapies. Cancer Manag Res 2020; 12:9869-9882. [PMID: 33116845 PMCID: PMC7553623 DOI: 10.2147/cmar.s251223] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/21/2020] [Indexed: 01/04/2023] Open
Abstract
Each year, colorectal cancers (CRCs) affect over a quarter of a million people. The risk of developing CRC in industrialized nations is approximately 5%. When the disease is localised, treatment success rates range from 70-90%; however, advanced CRC has a high mortality rate, consistently ranking in the top three causes of cancer-related deaths. There is a large geographic difference in global distribution, and CRC is predominantly associated with developed countries and a Western lifestyle and diet. As such, the developed world accounts for more than 63% of all cases of CRC. Geographic variations also predict cancer outcomes, which differ between racial and ethnic groups. This variation is due to inequalities in wealth, differences in the exposure to risk factors and barriers to high-quality cancer prevention, early detection and treatment. The aim of this paper was to review CRC in low- and middle-income countries such as South Africa, India, Brazil and China, and compare them with high-income countries such as the United States of America and the United Kingdom. It is important to note that these economically less developed countries, with historically low CRC rates, are experiencing an increased frequency of CRC. The review also discusses biological markers and genetic pathways involved in the development of colorectal cancer. Genes known to be responsible for the most common forms of inherited CRCs have also been identified but more remain to be identified. This would provide more candidate genes to be added to known biomarkers. CRC burden can be controlled through the widespread application of existing knowledge, such as reduced smoking habits, vaccination, early detection and promoting physical activity, accompanied by a healthy diet. An increased understanding of the molecular mechanisms and events underlying colorectal carcinogenesis will enable the development of new targets and therapeutic drugs.
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Affiliation(s)
- Rodney Hull
- SAMRC/UP Precision Prevention & Novel Drug Targets for HIV-Associated Cancers (PPNDTHAC) Extramural Unit, Pan African Cancer Research Institute (PACRI), University of Pretoria, Faculty of Health Sciences, Hatfield 0028, South Africa
| | - Flavia Zita Francies
- SAMRC/UP Precision Prevention & Novel Drug Targets for HIV-Associated Cancers (PPNDTHAC) Extramural Unit, Pan African Cancer Research Institute (PACRI), University of Pretoria, Faculty of Health Sciences, Hatfield 0028, South Africa
| | - Meryl Oyomno
- Department of Surgery, Faculty of Health Sciences, Steve Biko Academic Hospital and the University of Pretoria, Pretoria 0007, South Africa
| | - Zodwa Dlamini
- SAMRC/UP Precision Prevention & Novel Drug Targets for HIV-Associated Cancers (PPNDTHAC) Extramural Unit, Pan African Cancer Research Institute (PACRI), University of Pretoria, Faculty of Health Sciences, Hatfield 0028, South Africa.,Faculty of Health Sciences, School of Clinical Medicine, University of the Witwatersrand, Parktown 2193, South Africa
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9
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Roslan NH, Makpol S, Mohd Yusof YA. A Review on Dietary Intervention in Obesity Associated Colon Cancer. Asian Pac J Cancer Prev 2019; 20:1309-1319. [PMID: 31127882 PMCID: PMC6857900 DOI: 10.31557/apjcp.2019.20.5.1309] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 04/22/2019] [Indexed: 12/13/2022] Open
Abstract
Background: Colorectal cancer (CRC) is one of the major causes of morbidity and mortality. According to National Cancer Registry, the incidence of colorectal cancer in Peninsular Malaysia increases with age. The incidence is highest among Chinese population but lower among Indians and Malays. Many reviews have suggested that obesity may be associated with a higher risk (>50%) of colorectal cancer. Methods: This study collects a comprehensive data from the literature review available from respective journals on dietary intervention and the chemo-protective mechanisms of a few natural resources in obesity -associated colon cancer based on previous and current studies. Results: In obesity-associated colon cancer, the genes of interest and pathways that are mainly involved include NFκB, P13K/Akt, and MAPK pathways, and FTO, leptin, Cyclin D, MMPs, and STAT3 genes. Dietary modification is one of the alternative steps in early prevention of colon cancer. It has been proposed that the components present in certain foods may have the ability to protect against many diseases including the prevention of cancer. Conclusion: There are many factors that lead to obesity-associated colon cancer and the mechanisms behind it is still undergoing intensive research. This review aims to scrutinize research as well as reviews that have been previously reported on obesity associated colorectal cancer and the beneficial effects of including antioxidants-rich foods such as vegetables and fruits in the diet to reduce the risk of obesity associated colorectal cancer.
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Affiliation(s)
- N H Roslan
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur, Malaysia.
| | - S Makpol
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur, Malaysia.
| | - Y A Mohd Yusof
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur, Malaysia.
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Pouya F, Mojtabanezhad Shariatpanahi A, Ghaffarzadegan K, Tabatabaee Yazdi SA, Golmohammadzadeh H, Soltani G, Aminian Toosi K, Kerachian MA. A novel large germ line deletion in adenomatous polyposis coli (APC) gene associated with familial adenomatous polyposis. Mol Genet Genomic Med 2018; 6:1031-1040. [PMID: 30259713 PMCID: PMC6305644 DOI: 10.1002/mgg3.479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 12/12/2022] Open
Abstract
Background Familial adenomatous polyposis (FAP) is a familial colorectal cancer predisposition syndrome characterized by the development of numerous colorectal polyps, which is inherited in an autosomal dominant manner. FAP is caused by germ line mutations in adenomatous polyposis coli (APC) gene. Here, we described the identification of a causative APC gene deletion associated with FAP in an Iranian family. Methods Diagnosis of FAP was based on clinical findings, family history, and medical records (colonoscopy and histopathological data) after the patients were referred to Reza Radiotherapy and Oncology Center, Iran, for colonoscopy. Blood samples were collected, and genomic DNA was extracted. APC mutation screening was conducted by target next‐generation sequencing and quantitative real‐time PCR. Results A novel heterozygous large deletion mutation, c.(135+1_136–1)_(*2113+1_*2114–1) spanning exon 3 to 16 [EX3_16 DEL] of APC gene (GenBank Accession# MG712911), was detected in a proband and all her affected relatives in five generations, which was absent in unaffected family members and normal controls. Conclusions This novel deletion is the first report, describing the largest deletion of APC gene. Our novel finding contributes to a more comprehensive database of germ line mutations of APC gene that could be used in medical practice for the molecular diagnosis, risk assessment susceptibility of the disease for the FAP patients.
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Affiliation(s)
- Farzaneh Pouya
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Kamran Ghaffarzadegan
- Razavi Cancer Research Center, Razavi Hospital, Imam Reza International University, Mashhad, Iran
| | | | - Hamed Golmohammadzadeh
- Endoscopic and Minimally Invasive Surgery Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ghodratollah Soltani
- Cancer Genetics Research Unit, Reza Radiotherapy and Oncology Center, Mashhad, Iran
| | - Kian Aminian Toosi
- Cancer Genetics Research Unit, Reza Radiotherapy and Oncology Center, Mashhad, Iran.,Department of Biology, Islamic Azad University Mashhad Branch, Mashhad, Iran
| | - Mohammad Amin Kerachian
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Cancer Genetics Research Unit, Reza Radiotherapy and Oncology Center, Mashhad, Iran.,Cancer Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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11
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Hamzehzadeh L, Yousefi M, Ghaffari SH. Colorectal Cancer Screening: A Comprehensive Review to Recent Non-Invasive Methods. Int J Hematol Oncol Stem Cell Res 2017; 11:250-261. [PMID: 28989593 PMCID: PMC5625477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Colorectal cancer (CRC) is one of the most common cancers worldwide and considered to be one of the hassles in medical communities. CRC develops from precancerous polyps in the colon or rectum and is preventable and curable by an early diagnosis and with the removal of premalignant polyps. In recent years, scientists have looked for inexpensive and safe ways to detect CRC in its earliest stages. Strong evidence shows that screening for CRC is a crucial way to reduce the incidence and mortality of this devastating disease. The main purpose for screening is to detect cancer or pre-cancer signs in all asymptomatic patients. In this review, we holistically introduce major pathways involved in the initiation and progression of colorectal tumorgenesis, which mainly includes chromosome instability (CIN), microsatellite instability (MSI), the CpG island methylator phenotype (CIMP), and we then will discuss different screening tests and especially the latest non-invasive fecal screening test kits for the detection of CRC.
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Affiliation(s)
- Leila Hamzehzadeh
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Meysam Yousefi
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran,Hematology, Oncology and Stem Cell Transplantation Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed-Hamidollah Ghaffari
- Hematology, Oncology and Stem Cell Transplantation Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
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12
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Eshghifar N, Farrokhi N, Naji T, Zali M. Tumor suppressor genes in familial adenomatous polyposis. GASTROENTEROLOGY AND HEPATOLOGY FROM BED TO BENCH 2017; 10:3-13. [PMID: 28331559 PMCID: PMC5346818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Colorectal cancer (CRC) is mostly due to a series of genetic alterations that are being greatly under the influence of the environmental factors. These changes, mutational or epigenetic modifications at transcriptional forefront and/or post-transcriptional effects via miRNAs, include inactivation and the conversion of proto-oncogene to oncogenes, and/or inactivation of tumor suppressor genes (TSG). Here, a thorough review was carried out on the role of TSGs with the focus on the APC as the master regulator, mutated genes and mal-/dysfunctional pathways that lead to one type of hereditary form of the CRC; namely familial adenomatous polyposis (FAP). This review provides a venue towards defining candidate genes that can be used as new PCR-based markers for early diagnosis of FAP. In addition to diagnosis, defining the modes of genetic alterations will open door towards genome editing to either suppress the disease or reduce its progression during the course of action.
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Affiliation(s)
- Nahal Eshghifar
- Department of Molecular and Cellular Sciences, Faculty of Advanced Sciences & Technology, Pharmaceutical Science Branch, Islamic Azad University, Tehran, Iran
| | - Naser Farrokhi
- Department of Plant Biology & Biotechnology, Faculty of Biosciences & Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Tahereh Naji
- Department of Molecular and Cellular Sciences, Faculty of Advanced Sciences & Technology, Pharmaceutical Science Branch, Islamic Azad University, Tehran, Iran
| | - Mohammadreza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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High-resolution Melting Analysis for Gene Scanning of Adenomatous Polyposis Coli (APC) Gene With Oral Squamous Cell Carcinoma Samples. Appl Immunohistochem Mol Morphol 2016; 24:97-104. [PMID: 26447891 DOI: 10.1097/pai.0000000000000158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND There have been many different mutations reported for the large adenomatous polyposis coli (APC) tumor suppressor gene. APC mutations result in inactivation of APC tumor suppressor action, allowing the progression of tumorigenesis. The present study utilized a highly efficient method to identify APC mutations and investigated the association between the APC genetic variants Y486Y, A545A, T1493T, and D1822V and susceptibility to oral squamous cell carcinoma (OSCC). METHODS High-resolution melting (HRM) analysis was used to characterize APC mutations. Genomic DNA was extracted from 83 patient specimens of OSCC and 50 blood samples from healthy control subjects. The 14 exons and mutation cluster region of exon 15 were screened by HRM analysis. All mutations were confirmed by direct DNA sequencing. RESULTS Three mutations and 4 single nucleotide polymorphisms (SNPs) were found in this study. The mutations were c.573T>C (Y191Y) in exon 5, c.1005A>G (L335L) in exon 9, and c.1488A>T (T496T) in exon 11. Two SNPs, c.4479G>A (T1493T) and c.5465A>T (D1822V), were located in exon 15, whereas c.1458T>C (Y486Y) and c.1635G>A (A545A) were located in exon 11 and 13, respectively. There was no observed association between OSCC risk and genotype for any of the 4 APC SNPs. CONCLUSIONS The mutation of APC is rare in Taiwanese patients with OSCC. HRM analysis is a reliable, accurate, and fast screening method for APC mutations.
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High-resolution melting (HRM) re-analysis of a polyposis patients cohort reveals previously undetected heterozygous and mosaic APC gene mutations. Fam Cancer 2016; 14:247-57. [PMID: 25604157 PMCID: PMC4430602 DOI: 10.1007/s10689-015-9780-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Familial adenomatous polyposis is most frequently caused by pathogenic variants in either the APC gene or the MUTYH gene. The detection rate of pathogenic variants depends on the severity of the phenotype and sensitivity of the screening method, including sensitivity for mosaic variants. For 171 patients with multiple colorectal polyps without previously detectable pathogenic variant, APC was reanalyzed in leukocyte DNA by one uniform technique: high-resolution melting (HRM) analysis. Serial dilution of heterozygous DNA resulted in a lowest detectable allelic fraction of 6 % for the majority of variants. HRM analysis and subsequent sequencing detected pathogenic fully heterozygous APC variants in 10 (6 %) of the patients and pathogenic mosaic variants in 2 (1 %). All these variants were previously missed by various conventional scanning methods. In parallel, HRM APC scanning was applied to DNA isolated from polyp tissue of two additional patients with apparently sporadic polyposis and without detectable pathogenic APC variant in leukocyte DNA. In both patients a pathogenic mosaic APC variant was present in multiple polyps. The detection of pathogenic APC variants in 7 % of the patients, including mosaics, illustrates the usefulness of a complete APC gene reanalysis of previously tested patients, by a supplementary scanning method. HRM is a sensitive and fast pre-screening method for reliable detection of heterozygous and mosaic variants, which can be applied to leukocyte and polyp derived DNA.
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15
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Establishing a clinical and molecular diagnosis for hereditary colorectal cancer syndromes: Present tense, future perfect? Gastrointest Endosc 2014; 80:1145-55. [PMID: 25434663 DOI: 10.1016/j.gie.2014.07.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 07/23/2014] [Indexed: 02/08/2023]
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Yamaguchi T, Koizumi K, Arai M, Tamura K, Iijima T, Horiguchi SI, Miyaki M. A large deletion of chromosome 5q22.1-22.2 associated with sparse type of familial adenomatous polyposis: report of a case. Jpn J Clin Oncol 2014; 44:1243-7. [PMID: 25324480 DOI: 10.1093/jjco/hyu150] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The proband was a 32-year-old man with sparse type of familial adenomatous polyposis with fundic gland and duodenal polyps and congenital hypertrophy of the retinal pigment epithelium without osteoma, dental abnormalities and desmoid tumors. Direct DNA sequencing did not detect germline mutations in any APC exon. However, using the multiplex ligation-dependent probe amplification method, we detected germline deletions of all APC exons. Using dual-color fluorescence in situ hybridization, we identified germline deletion of locus 5q22.1-22.2 that includes APC. Analysis of colorectal tumors identified somatic APC mutations in the cluster region in all polyps, but no loss of heterozygosity was detected in any polyp.
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Affiliation(s)
- Tatsuro Yamaguchi
- Hereditary Tumor Research Project, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| | - Koichi Koizumi
- Department of Gastroenterology, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| | - Masami Arai
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Kazuo Tamura
- Major in Science, Graduate School of Science and Engineering Research, Kinki University, Higashiosaka
| | - Takeru Iijima
- Hereditary Tumor Research Project, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| | - Shin-Ichiro Horiguchi
- Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan
| | - Michiko Miyaki
- Hereditary Tumor Research Project, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
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17
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Lee GH, Payne SJ, Melville A, Clark SK. Genetic testing in inherited polyposis syndromes - how and why? Colorectal Dis 2014; 16:595-602. [PMID: 24612292 DOI: 10.1111/codi.12600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/05/2013] [Indexed: 02/08/2023]
Abstract
There have been recent advances in genetic testing enabling accurate diagnosis of polyposis syndromes by identifying causative gene mutations, which is essential in the management of individuals with polyposis syndrome and predictive genetic testing of their extended families. There are some similarities in clinical presentation of various polyposis syndromes, which may pose a challenge to diagnosis. In this review, we discuss the clinical presentation of the main polyposis syndromes and the process of genetic testing, including the latest advancement and future of genetic testing. We aim to reiterate the importance of genetic testing in the management of polyposis syndromes, potential pitfalls associated with genetic testing and recommendations for healthcare professionals involved with the care of polyposis patients.
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Affiliation(s)
- G H Lee
- The Polyposis Registry, St Mark's Hospital, Harrow, UK; Department of Surgery and Cancer, Imperial College London, London, UK
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18
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Casper M, Petek E, Henn W, Niewald M, Schneider G, Zimmer V, Lammert F, Raedle J. Multidisciplinary treatment of desmoid tumours in Gardner's syndrome due to a large interstitial deletion of chromosome 5q. QJM 2014; 107:521-7. [PMID: 24554300 DOI: 10.1093/qjmed/hcu036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND AIMS Classic autosomal-dominant familial adenomatous polyposis (FAP) is clinically defined by the development of hundreds to thousands of colorectal adenomas beginning in childhood and adolescence. A variant of FAP characterized by polyposis in combination with osteomas or soft tissue tumours is called Gardner's syndrome. FAP is caused by germline inactivation of the APC (adenomatous polyposis coli) tumour-suppressor gene located on the long arm of chromosome 5 (5q21-5q22). Cytogenetically visible deletions of chromosome 5q encompassing APC have very rarely been reported. Here, we aimed to phenotypically and genetically characterize a patient with a heterozygous 5q deletion resulting in Gardner's syndrome. METHODS AND RESULTS A 26-year-old female patient with mild mental handicap and dysmorphic features due to a cytogenetically visible deletion on chromosome 5q (microscopically estimated region 5q14-5q23) presented at our tertiary referral centre because of mild adenomatous polyposis (<500 polyps). Twenty months after prophylactic proctocolectomy with definitive ileostomy, three rapidly growing desmoids were observed. Tumour-associated complications necessitated a multidisciplinary approach including medical treatment, surgery and radiation therapy. The characterization of the deletion by comparative genomic hybridization identified a large 5q deletion expanding over a 20-Mb region (5q21.3-5q23.3) including the APC gene. CONCLUSION Chromosome deletions must be suspected in patients presenting with FAP together with mental handicap and dysmorphic features. This case also impressively shows that FAP-associated desmoids need multimodal treatment taking into account the patient's individual symptoms, disease progression and tumour location.
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Affiliation(s)
- M Casper
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - E Petek
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - W Henn
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - M Niewald
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - G Schneider
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - V Zimmer
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - F Lammert
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
| | - J Raedle
- From the Department of Medicine II, Saarland University Medical Center, Homburg, Germany, Institute of Medical Biology and Human Genetics, Medical University Graz, Graz, Austria, Institute of Human Genetics, Saarland University Medical Center, Homburg, Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg, Department of Radiology, Saarland University Medical Center, Homburg and Department of Medicine 3, Westpfalz Hospital, Kaiserslautern, Germany
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Aihara H, Kumar N, Thompson CC. Diagnosis, surveillance, and treatment strategies for familial adenomatous polyposis: rationale and update. Eur J Gastroenterol Hepatol 2014; 26:255-62. [PMID: 24161962 PMCID: PMC5019104 DOI: 10.1097/meg.0000000000000010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Familial adenomatous polyposis is characterized by the development of multiple (>100) colorectal adenomas throughout the colorectum. This disorder can be caused by a germline mutation in the adenomatous polyposis coli gene and can be diagnosed either clinically or genetically. After diagnosis with the condition, patients should undergo prophylactic proctocolectomy with a neoreservoir, usually an ileoanal pouch, at an appropriate time. Individuals with a family history of this disease who have not been diagnosed should be advised to attend genetic counseling and to enroll in appropriate clinical and genetic surveillance programs. Recent progress in endoscopic technology, including high-resolution endoscopy, capsule endoscopy, and double-balloon endoscopy, has made possible more detailed and wide-ranging investigation of the gastrointestinal tract. Although there has been limited evidence, further studies on these new endoscopic technologies might alter the surveillance strategies for familial adenomatous polyposis.
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Affiliation(s)
- Hiroyuki Aihara
- Division of Gastroenterology and Hepatology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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20
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Colussi D, Brandi G, Bazzoli F, Ricciardiello L. Molecular pathways involved in colorectal cancer: implications for disease behavior and prevention. Int J Mol Sci 2013; 14:16365-85. [PMID: 23965959 PMCID: PMC3759916 DOI: 10.3390/ijms140816365] [Citation(s) in RCA: 313] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 07/25/2013] [Accepted: 07/26/2013] [Indexed: 02/07/2023] Open
Abstract
Research conducted during the past 30 years has increased our understanding of the mechanisms involved in colorectal cancer initiation and development. The findings have demonstrated the existence of at least three pathways: chromosomal instability, microsatellite instability and CpG island methylator phenotype. Importantly, new studies have shown that inflammation and microRNAs contribute to colorectal carcinogenesis. Recent data have demonstrated that several genetic and epigenetic changes are important in determining patient prognosis and survival. Furthermore, some of these mechanisms are related to patients’ response to drugs, such as aspirin, which could be used for both chemoprevention and treatment in specific settings. Thus, in the near future, we could be able to predict disease behavior based on molecular markers found on tumors, and direct the best treatment options for patients.
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Affiliation(s)
- Dora Colussi
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti 9, Pad 5, Bologna 40138, Italy; E-Mails: (D.C.); (F.B.)
| | - Giovanni Brandi
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Via Massarenti 9, Pad 5, Bologna 40138, Italy; E-Mail:
| | - Franco Bazzoli
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti 9, Pad 5, Bologna 40138, Italy; E-Mails: (D.C.); (F.B.)
| | - Luigi Ricciardiello
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti 9, Pad 5, Bologna 40138, Italy; E-Mails: (D.C.); (F.B.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-51-6363-381; Fax: +39-51-343-926
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21
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Abstract
Adenomatous polyposis coli (APC) is best known for its crucial role in colorectal cancer suppression. Rodent models with various Apc mutations have enabled experimental validation of different Apc functions in tumors and normal tissues. Since the development of the first mouse model with a germline Apc mutation in the early 1990s, 20 other Apc mouse and rat models have been generated. This article compares and contrasts currently available Apc rodent models with particular emphasis on providing potential explanations for their reported variation in three areas: (i) intestinal polyp multiplicity, (ii) intestinal polyp distribution, and (iii) extraintestinal phenotypes.
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Affiliation(s)
- Maged Zeineldin
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave. Lawrence, KS 66045 USA
| | - Kristi L. Neufeld
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave. Lawrence, KS 66045 USA
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22
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Marquis-Nicholson R, Prosser D, Love JM, Love DR. Gene Dosage Analysis in a Clinical Environment: Gene-Targeted Microarrays as the Platform-of-Choice. ACTA ACUST UNITED AC 2013; 2:51-62. [PMID: 27605180 PMCID: PMC5003480 DOI: 10.3390/microarrays2020051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/18/2013] [Accepted: 03/20/2013] [Indexed: 01/11/2023]
Abstract
The role of gene deletion and duplication in the aetiology of disease has become increasingly evident over the last decade. In addition to the classical deletion/duplication disorders diagnosed using molecular techniques, such as Duchenne Muscular Dystrophy and Charcot-Marie-Tooth Neuropathy Type 1A, the significance of partial or whole gene deletions in the pathogenesis of a large number single-gene disorders is becoming more apparent. A variety of dosage analysis methods are available to the diagnostic laboratory but the widespread application of many of these techniques is limited by the expense of the kits/reagents and restrictive targeting to a particular gene or portion of a gene. These limitations are particularly important in the context of a small diagnostic laboratory with modest sample throughput. We have developed a gene-targeted, custom-designed comparative genomic hybridisation (CGH) array that allows twelve clinical samples to be interrogated simultaneously for exonic deletions/duplications within any gene (or panel of genes) on the array. We report here on the use of the array in the analysis of a series of clinical samples processed by our laboratory over a twelve-month period. The array has proven itself to be robust, flexible and highly suited to the diagnostic environment.
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Affiliation(s)
- Renate Marquis-Nicholson
- Diagnostic Genetics, LabPLUS, Auckland City Hospital, P.O. Box 110031, Auckland 1148, New Zealand.
| | - Debra Prosser
- Diagnostic Genetics, LabPLUS, Auckland City Hospital, P.O. Box 110031, Auckland 1148, New Zealand.
| | - Jennifer M Love
- Diagnostic Genetics, LabPLUS, Auckland City Hospital, P.O. Box 110031, Auckland 1148, New Zealand.
| | - Donald R Love
- Diagnostic Genetics, LabPLUS, Auckland City Hospital, P.O. Box 110031, Auckland 1148, New Zealand.
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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23
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Marquis-Nicholson R, Doherty E, Love JM, Lan CC, George AM, Thrush A, Love DR. Array-based Identification of Copy Number Changes in a Diagnostic Setting: Simultaneous gene-focused and low resolution whole human genome analysis. Sultan Qaboos Univ Med J 2013; 13:69-79. [PMID: 23573385 DOI: 10.12816/0003198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 09/06/2012] [Accepted: 10/06/2012] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVES The aim of this study was to develop and validate a comparative genomic hybridisation (CGH) array that would allow simultaneous targeted analysis of a panel of disease genes and low resolution whole genome analysis. METHODS A bespoke Roche NimbleGen 12x135K CGH array (Roche NimbleGen Inc., Madison, Wisconsin, USA) was designed to interrogate the coding regions of 66 genes of interest, with additional widely-spaced backbone probes providing coverage across the whole genome. We analysed genomic deoxyribonucleic acid (DNA) from 20 patients with a range of previously characterised copy number changes and from 8 patients who had not previously undergone any form of dosage analysis. RESULTS The custom-designed Roche NimbleGen CGH array was able to detect known copy number changes in all 20 patients. A molecular diagnosis was also made for one of the additional 4 patients with a clinical diagnosis that had not been confirmed by sequence analysis, and carrier testing for familial copy number variants was successfully completed for the remaining four patients. CONCLUSION The custom-designed CGH array described here is ideally suited for use in a small diagnostic laboratory. The method is robust, accurate, and cost-effective, and offers an ideal alternative to more conventional targeted assays such as multiplex ligation-dependent probe amplification.
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Jahng J, Yoon SJ, Park H. A Novel Germline Mutation in Exon 15 of the APC Gene in Attenuated Familial Adenomatous Polyposis: A Report of Two Cases. Gut Liver 2013; 7:120-5. [PMID: 23423322 PMCID: PMC3572313 DOI: 10.5009/gnl.2013.7.1.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 05/20/2011] [Indexed: 02/06/2023] Open
Abstract
Attenuated familial adenomatous polyposis (AFAP) is a variant of familial adenomatous polyposis with fewer than one hundred colorectal polyps and a later age of onset of the cancer. Here, we report two cases of AFAP within family members. Each patient demonstrated the same novel germ line mutation in exon 15 of the adenomatous polyposis coli (APC) gene and was successfully managed with sulindac after refusal to perform colectomy: a 23-year-old man with incidentally diagnosed gastric adenoma and fundic gland polyps underwent colonoscopy, and fewer than 100 colorectal polyps were found; a 48-year-old woman who happened to be the mother of the 23-year-old man also showed fewer than 100 colorectal polyps on colonoscopy. Genetic analysis revealed a novel frameshift mutation in exon 15 of the APC gene. The deletion of adenine-guanine with the insertion of thymine in c.3833-3834 resulted in the formation of stop codon 1,287 in both patients. The patients were treated with sulindac due to their refusal to undergo colectomy. The annual follow-up upper endoscopy and colonoscopy in the following 2 years revealed significant regression of the colorectal polyps in both patients.
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Affiliation(s)
- Jaehoon Jahng
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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25
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Ebenazer A, Rajaratnam S, Pai R. Detection of large deletions in the VHL gene using a Real-Time PCR with SYBR Green. Fam Cancer 2013; 12:519-24. [DOI: 10.1007/s10689-013-9606-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zeineldin M, Neufeld KL. More than two decades of Apc modeling in rodents. Biochim Biophys Acta Rev Cancer 2013; 1836:80-9. [PMID: 23333833 DOI: 10.1016/j.bbcan.2013.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/31/2012] [Accepted: 01/03/2013] [Indexed: 02/07/2023]
Abstract
Mutation of tumor suppressor gene adenomatous polyposis coli (APC) is an initiating step in most colon cancers. This review summarizes Apc models in mice and rats, with particular concentration on those most recently developed, phenotypic variation among different models, and genotype/phenotype correlations.
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Affiliation(s)
- Maged Zeineldin
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
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27
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Naem E, Haas MJ, Wong NCW, Mooradian AD. Endoplasmic reticulum stress in HepG2 cells inhibits apolipoprotein A-I secretion. Life Sci 2012; 92:72-80. [PMID: 23154241 DOI: 10.1016/j.lfs.2012.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/03/2012] [Accepted: 10/30/2012] [Indexed: 10/27/2022]
Abstract
AIMS Endoplasmic reticulum (ER) stress modulates gene expression and has been implicated in causing dyslipidemias. To determine if ER stress may contribute to hypoalphalipoproteinemia through suppression of apo A-I gene expression, human hepatoma cell line Hep G2 was treated with ER stress inducers and the changes in apo A-I gene expression were compared to albumin gene expression. MAIN METHODS HepG2 cells were treated with tunicamycin (TM) and thapsigargin (TG), two potent inducers of ER stress, and apo A-I and albumin protein levels, mRNA levels, and promoter activity were measured. ER stress was measured using the ER stress-responsive alkaline phosphatase assay and by Western blot quantitation of ER stress markers such as glucose-regulated protein-78 (GRP-78), phosphorylated Jun N-terminal kinase (phospho-JNK), total JNK, phosphorylated eukaryotic initiation factor 2 alpha (phospho eIF2α), and total eIF2α. KEY FINDINGS TM and TG induced ER stress in HepG2 cells and reduced apo A-I and albumin secretion in a dose-dependent manner. Intracellular albumin levels increased in cells treated with TM and TG while intracellular apo A-I levels decreased. Albumin mRNA and albumin gene promoter activity were reduced in proportion to the decrease in albumin secreted while changes in the apo A-I mRNA levels and promoter activity were modest and did not account for the reduction in apo A-I secretion. SIGNIFICANCE These results indicate that apo A-I secretion is inhibited by ER stress possibly by affecting cellular degradation pathways. However, ER stress does not affect apo A-I secretion by regulating gene expression.
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Affiliation(s)
- Emad Naem
- The Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Florida, Jacksonville College of Medicine, Jacksonville, FL 32209, USA
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James AS, Chisholm P, Wolin KY, Baxter M, Kaphingst K, Davidson NO. Screening and Health Behaviors among Persons Diagnosed with Familial Adenomatous Polyposis and Their Relatives. J Cancer Epidemiol 2012; 2012:506410. [PMID: 22899922 PMCID: PMC3414059 DOI: 10.1155/2012/506410] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 06/08/2012] [Accepted: 06/19/2012] [Indexed: 01/02/2023] Open
Abstract
Familial Adenomatous Polyposis (FAP) is a rare autosomal dominantly inherited colorectal cancer syndrome. Individuals with FAP often undergo colectomy and are recommended to follow several surveillance protocols. Biological relatives of persons with FAP may also be at risk and thus should undergo genetic counseling. Screening adherence, genetic testing, and other health behaviors among individuals with FAP and their relatives are not well characterized. We conducted a cross-sectional self-report survey with individuals who have FAP (n = 35) and their biological relatives (n = 15). Respondents were recruited through a cancer center registry for inherited colon cancers. Most relatives had undergone colon cancer screening; 40% had undergone genetic testing. One fifth of respondents with FAP had not undergone an upper endoscopy, contrary to usual recommendations. Cigarette smoking rates were above average and were higher among FAP respondents. Use of vitamin supplements was fairly common, more so among those with FAP. Although most people had been screened, there are areas for improvement, notably for upper endoscopy among individuals with FAP and genetic testing among family members. Several other health-risk behaviors and health concerns other than FAP were identified. Further research into factors contributing to screening rates and other health behaviors in this high-risk population is warranted.
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Affiliation(s)
- Aimee S. James
- Division of Public Health Sciences, Department of Surgery, Washington University in Saint Louis, 660 So. Euclid Avenue, P.O. Box 8100, Saint Louis, MO 63110, USA
| | - Phillip Chisholm
- Department of Medicine, Washington University in Saint Louis, 4950 Children's place St. Louis, MO 63110, USA
| | - Kathleen Y. Wolin
- Division of Public Health Sciences, Department of Surgery, Washington University in Saint Louis, 660 So. Euclid Avenue, P.O. Box 8100, Saint Louis, MO 63110, USA
| | - Melanie Baxter
- Siteman Cancer Center, Washington University in Saint Louis, 660 So. Euclid Avenue, P.O. Box 8100, Saint Louis, MO 63110, USA
| | - Kimberly Kaphingst
- Division of Public Health Sciences, Department of Surgery, Washington University in Saint Louis, 660 So. Euclid Avenue, P.O. Box 8100, Saint Louis, MO 63110, USA
| | - Nicholas O. Davidson
- Division of Gastroenterology, Department of Medicine, Washington University in Saint Louis, 660 So. Euclid Avenue, P.O. Box 8124, Saint Louis, MO 63110, USA
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Wang J, Zhan H, Li FY, Pursley AN, Schmitt ES, Wong LJ. Targeted array CGH as a valuable molecular diagnostic approach: experience in the diagnosis of mitochondrial and metabolic disorders. Mol Genet Metab 2012; 106:221-30. [PMID: 22494545 DOI: 10.1016/j.ymgme.2012.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 03/09/2012] [Accepted: 03/09/2012] [Indexed: 11/29/2022]
Abstract
Oligonucleotide array-based comparative genomic hybridization (aCGH) targeted to coding exons of genes of interest has been proven to be a valuable diagnostic tool to complement with Sanger sequencing for the detection of large deletions/duplications. We have developed a custom designed oligonucleotide aCGH platform for this purpose. This array platform provides tiled coverage of the entire mitochondrial genome and high-density coverage of a set of nuclear genes involving mitochondrial and metabolic disorders and can be used to evaluate large deletions in targeted genes. A total of 1280 DNA samples from patients suspected of having mitochondrial or metabolic disorders were evaluated using this targeted aCGH. We detected 40 (3%) pathogenic large deletions in unrelated individuals, including 6 in genes responsible for mitochondrial DNA (mtDNA) depletion syndromes, 23 in urea cycle genes, 11 in metabolic and related genes. Deletion breakpoints have been confirmed in 31 cases by PCR and sequencing. The possible deletion mechanism has been discussed. These results illustrate the successful utilization of targeted aCGH to detect large deletions in nuclear and mitochondrial genomes. This technology is particularly useful as a complementary diagnostic test in the context of a recessive disease when only one mutant allele is found by sequencing. For female carriers of X-linked disorders, if sequencing analysis does not detect point mutations, targeted aCGH should be considered for the detection of large heterozygous deletions.
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Affiliation(s)
- Jing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
Array comparative genomic hybridization (aCGH) is a powerful clinical diagnostic tool that can be used to evaluate copy number changes in the genome. Targeted aCGH provides a much higher resolution in targeted gene regions to detect copy number changes within single gene or single exon. A custom-designed oligonucleotide aCGH platform (MitoMet(®)) has been developed to provide tiled coverage of the entire 16.6-kb mitochondrial genome and high-density coverage of a set of nuclear genes associated with metabolic and mitochondrial related disorders, for quick evaluation of copy number changes in both genomes (1). The high-density probes in mitochondrial genome on the MitoMet(®) array allow estimation of mtDNA deletion breakpoints and deletion heteroplasmy (2). This technology is particularly useful as a complementary diagnostic test to detect large deletions in genes related to mitochondrial disorders.
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Burger B, Cattani N, Trueb S, de Lorenzo R, Albertini M, Bontognali E, Itin C, Schaub N, Itin PH, Heinimann K. Prevalence of skin lesions in familial adenomatous polyposis: a marker for presymptomatic diagnosis? Oncologist 2011; 16:1698-705. [PMID: 22135120 DOI: 10.1634/theoncologist.2011-0244] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND AND AIMS Benign skin tumors such as lipomas, fibromas, and epidermal cysts are among the extracolonic manifestations of familial adenomatous polyposis (FAP). Readily detectable by inspection, they could serve as presymptomatic diagnostic markers to identify FAP patients. We therefore prospectively determined the prevalence of cutaneous lesions in genetically confirmed adenomatous polyposis coli (APC) mutation carriers and assessed their potential usefulness in the identification of FAP patients. METHODS Whole-skin examination was performed in 56 adult APC mutation carriers, compared with a control group (n = 116). In addition, FAP patients were investigated for the presence of congenital hypertrophy of the retinal pigment epithelium (CHRPE), an established clinical marker for FAP, and a detailed review of medical records was performed. RESULTS Nearly half of all FAP patients (48.2%) had at least one FAP-associated skin lesion, compared with one third (34.5%) of controls. Only multiple lipomas and combined skin lesions were significantly more prevalent in APC mutation carriers. CHRPE was observed in 22 (43.1%) of 51 FAP patients, including 14 (37.8%) of 37 individuals with APC mutations outside the CHRPE-associated region between codons 311 and 1465. CONCLUSIONS Despite a significantly higher prevalence of multiple lipomas, occurring at younger age, and combined skin lesions in APC mutation carriers, the low diagnostic sensitivity of FAP-associated skin lesions precludes their use as markers for FAP in clinical practice. Based on our findings, the common CHRPE-associated region should be extended to APC codons 148-2043.
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Affiliation(s)
- Bettina Burger
- Research Group of Dermatology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland.
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Mutation analysis of the APC gene in unrelated Korean patients with FAP: four novel mutations with unusual phenotype. Fam Cancer 2011; 10:21-6. [PMID: 21110124 DOI: 10.1007/s10689-010-9363-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Germline mutations within the adenomatous polyposis coli (APC) gene are responsible for most cases of familial adenomatous polyposis (FAP), an autosomal dominantly inherited predisposition to colorectal cancer. To date more than 900 different APC germline mutations have been characterized worldwide demonstrating allelic heterogeneity. Here, we analyzed the APC gene in 23 DNA samples from unrelated Korean patients with the typical clinical symptoms of FAP by denaturing high-performance liquid chromatography (DHPLC) and direct sequencing. We identified 20 different APC sequence variants, including 9 truncating mutations, 1 missense mutation, 7 polymorphisms, and 3 intronic variants. Nine different truncating mutations, including four novel mutations (p.Leu180TyrfsX5, p.Gly567X, p.Ser1275PhefsX13, p.Leu1280CysfsX8), were detected. The most common mutation was a 5 bp deletion at codon 1,309 (p.Glu1309AspfsX4) as in Western studies. The next most common mutation was p.Ser1275PhefsX13 with a severe form of FAP with many extracolonic manifestations; this was a novel mutation identified in our study and may represent the second hot-spot mutation in a Korean population. Novel mutations are of particular interest because of the unusual phenotypic features shown by patients. In present study, we found new positions associated with thyroid cancer (codon 180) and desmoid tumor (codon 1,280), which have not been previously reported. The results of this molecular study have revealed the existence of novel pathogenic mutations in Korean patients with FAP. In addition to allowing phenotype-genotype correlations to be performed, these results are currently being used in genetic counseling and in patient care.
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Chen S, Zhou J, Zhang X, Zhou X, Zhu M, Zhang Y, Ma G, Li J. Mutation Analysis of the APC Gene in a Chinese FAP Pedigree with Unusual Phenotype. ISRN GASTROENTEROLOGY 2011; 2011:909121. [PMID: 22164339 PMCID: PMC3226247 DOI: 10.5402/2011/909121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Accepted: 01/19/2011] [Indexed: 12/22/2022]
Abstract
Background and Aim. Germline mutations of the adenomatous polyposis coli (APC) gene cause familial adenomatous polyposis (FAP), an autosomal dominant inherited disease mainly characterized by colorectal adenomatous polyposis. Genetic studies of FAP have shown that somatic APC mutations are dependent on the position of the germline APC mutation. However, the molecular mechanism underlying these genotype-phenotype associations for APC in Chinese remain largely unknown. Patients and Methods. In this study, we investigated the APC gene mutation in a Chinese FAP family by systematic screening with multiplex ligation-dependent probe amplification (MLPA), denaturing high-performance liquid chromatography (dHPLC), and DNA sequencing. Promoter methylation was detected by methylation-specific PCR. Results. The identical germline mutation c.1999 C>T (Q667X) of APC was identified in 5 affected members, among which 2 members carried somatic mutations of APC, one with promoter hypermethylation and the other with loss of wild-type allele in their adenomas. The somatic mutations were shown connected with the disease severity, demonstrating a unique genotype-phenotype association in this FAP pedigree. Conclusion. The study revealed the existence of novel pathogenic mutations in Chinese patients with FAP. Somatic mutations are of particular interest because of the unusual phenotypic features shown by patients.
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Affiliation(s)
- S Chen
- Laboratory of Genetics and Molecular Biology, Jiangsu Institute of Cancer Research, Nanjing 210009, China
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Cheung AF, Carter AM, Kostova KK, Woodruff JF, Crowley D, Bronson RT, Haigis KM, Jacks T. Complete deletion of Apc results in severe polyposis in mice. Oncogene 2010; 29:1857-64. [PMID: 20010873 PMCID: PMC2990498 DOI: 10.1038/onc.2009.457] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/09/2009] [Accepted: 11/12/2009] [Indexed: 12/12/2022]
Abstract
The adenomatous polyposis coli (APC) gene product is mutated in the vast majority of human colorectal cancers. APC negatively regulates the WNT pathway by aiding in the degradation of beta-catenin, which is the transcription factor activated downstream of WNT signaling. APC mutations result in beta-catenin stabilization and constitutive WNT pathway activation, leading to aberrant cellular proliferation. APC mutations associated with colorectal cancer commonly fall in a region of the gene termed the mutation cluster region and result in expression of an N-terminal fragment of the APC protein. Biochemical and molecular studies have revealed localization of APC/Apc to different sub-cellular compartments and various proteins outside of the WNT pathway that associate with truncated APC/Apc. These observations and genotype-phenotype correlations have led to the suggestion that truncated APC bears neomorphic and/or dominant-negative function that support tumor development. To analyze this possibility, we have generated a novel allele of Apc in the mouse that yields complete loss of Apc protein. Our studies reveal that whole-gene deletion of Apc results in more rapid tumor development than the APC multiple intestinal neoplasia (Apc(Min)) truncation. Furthermore, we found that adenomas bearing truncated Apc had increased beta-catenin activity when compared with tumors lacking Apc protein, which could lead to context-dependent inhibition of tumorigenesis.
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Affiliation(s)
- Ann F. Cheung
- Koch Institute and Department of Biology, MIT, Cambridge, MA
| | - Alia M. Carter
- Koch Institute and Department of Biology, MIT, Cambridge, MA
| | | | | | - Denise Crowley
- Koch Institute and Department of Biology, MIT, Cambridge, MA
- Howard Hughes Medical Institute, MIT, Cambridge, MA
| | - Roderick T. Bronson
- Department of Pathology, Tufts University School of Medicine and Veterinary Medicine, Boston, MA
| | - Kevin M. Haigis
- Masschusetts General Hospital Cancer Center, Harvard Medical School Department of Pathology, Charlestown, MA
| | - Tyler Jacks
- Koch Institute and Department of Biology, MIT, Cambridge, MA
- Howard Hughes Medical Institute, MIT, Cambridge, MA
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Al Fares A, Millington GWM, Tischkowitz M. Dermatological features of inherited cancer syndromes in adults. Clin Exp Dermatol 2010; 35:462-7. [DOI: 10.1111/j.1365-2230.2010.03811.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Thean LF, Loi C, Ho KS, Koh PK, Eu KW, Cheah PY. Genome-wide scan identifies a copy number variable region at 3q26 that regulates PPM1L in APC mutation-negative familial colorectal cancer patients. Genes Chromosomes Cancer 2010; 49:99-106. [PMID: 19847890 DOI: 10.1002/gcc.20724] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited form of colorectal cancer (CRC) caused by mutation in the adenomatous polyposis coli (APC) gene. However, APC mutations are not detected in 10-50% of FAP patients. We searched for a new cancer gene by performing genome-wide genotyping on members of an APC mutation-negative FAP variant family and ethnicity-matched healthy controls. No common copy number change was found in all affected members using the unaffected members and healthy controls as baseline. A 111 kb copy number variable (CNV) region at 3q26.1 was shown to have copy number loss in all eight polyps compared to matched lymphocytes of two affected members. A common region of loss in all polyps, which are precursors to CRC, is likely to harbor disease-causing gene in accordance to Knudsen's "two-hit" hypothesis. There is, however, no gene within the deleted region. A 2-Mb scan of the genomic region encompassing the deleted region identified PPM1L, coding for a novel serine-threonine phosphatase in the TGF-beta and BMP signaling pathways. Real-time PCR analyses indicate that the 3'UTR of PPM1L transcript was down-regulated more than two-folds in all six polyps and tumors compared to matched mucosa of the affected member. This down-regulation was not observed in APC mutation-positive FAP patients. Our results suggest that the CNV region at 3q26 harbors an element that regulates the expression of an upstream candidate tumor suppressor, PPM1L, thus providing a novel mechanism for colorectal tumorigenesis in APC mutation-negative familial CRC patients.
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Affiliation(s)
- L F Thean
- Department of Colorectal Surgery, Singapore General Hospital, Singapore, Republic of Singapore
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Abstract
Colon cancer closely follows the paradigm of a single "gatekeeper gene." Mutations inactivating the APC (adenomatous polyposis coli) gene are found in approximately 80% of all human colon tumors and heterozygosity for such mutations produces an autosomal dominant colon cancer predisposition in humans and in murine models. However, this tight association between a single genotype and phenotype belies a complex association of genetic and epigenetic factors that together generate the broad phenotypic spectrum ofboth familial and sporadic colon cancers. In this Chapter, we give a general overview of the structure, function and outstanding issues concerning the role of Apc in human and experimental colon cancer. The availability of increasingly close models for human colon cancer in genetically tractable animal species enables the discovery and eventual molecular identification of genetic modifiers of the Apc-mutant phenotypes, connecting the central role of Apc in colon carcinogenesis to the myriad factors that ultimately determine the course of the disease.
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Abstract
This article focuses on genetic testing for hereditary colorectal cancer syndromes. Genetic testing is now available in North America for all of the known hereditary colorectal cancer genes. In addition, most of these tests have improved significantly in the past few years with the inclusion of techniques to detect large rearrangements. As a result, clinicians are in a better position than ever to help families with these syndromes to identify the underlying genetic cause. This identification will ensure that they receive appropriate management, and will enable their relatives to determine their precise risks and to tailor their cancer surveillance.
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Affiliation(s)
- Heather Hampel
- Division of Human Genetics, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43240, USA.
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Chiang JM, Chen HW, Tang RP, Chen JS, Changchien CR, Hsieh PS, Wang JY. Mutation analysis of the APC gene in Taiwanese FAP families: low incidence of APC germline mutation in a distinct subgroup of FAP families. Fam Cancer 2009; 9:117-24. [PMID: 19768578 DOI: 10.1007/s10689-009-9292-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Accepted: 08/29/2009] [Indexed: 12/24/2022]
Abstract
Familial adenomatous polyposis (FAP) is an autosomal-dominant disease caused by germline mutations in the adenomatous polyposis coli (APC) gene. The affected individuals develop colorectal polyposis and show various extra-colonic manifestations. In this study, we aimed to investigate the genetic and clinical characteristics of FAP in Taiwanese families and analyze the genotype-phenotype correlations. Blood samples were obtained from 66 FAP patients registered in the hereditary colorectal cancer database. Then, germline mutations in the APC genes of these 66 polyposis patients from 47 unrelated FAP families were analyzed. The germline-mutation-negative cases were analyzed by performing multiplex ligation-dependent probe amplification (MLPA) and single-strand conformation polymorphism (SSCP) analysis of the MUTYH gene. Among the analyzed families, 79% (37/47) of the families showed 28 APC mutations, including 19 frameshift mutations, 4 nonsense mutations, 3 genomic deletion mutations, 1 missense mutation, and 1 splice-site mutation. In addition, we identified 15 novel mutations in 32% (15/47) of the families. The cases in which APC mutations were not identified showed significantly lower incidence of profuse polyposis (P = 0.034) and gastroduodenal polyps (P = 0.027). Furthermore, FAP families in which some affected individuals had less than 100 polyps showed significant association with low incidence of APC germline mutations (P = 0.002). We have added the APC germline-mutation data for Taiwanese FAP patients and indicated the presence of an FAP subgroup comprising affected individuals with nonadenomatous polyps or less than 100 adenomatous polyps; this form of FAP is less frequently caused by germline mutations of the APC gene.
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Affiliation(s)
- J M Chiang
- Division of Colon and Rectal Surgery, Chang Gung Memorial Hospital, Lin-kou, Taiwan.
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Liu X, Shan X, Friedl W, Uhlhaas S, Propping P, Li J, Wang Y. May the APC gene somatic mutations in tumor tissues influence the clinical features of Chinese sporadic colorectal cancers? Acta Oncol 2009; 46:757-62. [PMID: 17653897 DOI: 10.1080/02841860600996439] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The APC gene plays an important role in colorectal carcinogenesis. The impact of APC mutations on the clinical features in sporadic CRC remains to be uncovered. The APC gene was screened for mutations with systematic analysis techniques including DHPLC, PTT, MLPA and DNA sequencing in 43 Chinese sporadic CRC patients. Twenty nine somatic mutations (in 17 different types) in APC gene were found in 18 of 43 sporadic CRC patients. Of those, nine were novel mutations. Higher frequency of somatic APC mutations was found in younger CRC patients than that in elder ones. The biallelic somatic mutations of APC gene were identified in four CRC patients whose tumors had more invasive clinical features. The nonsense mutation Arg1114X in APC gene was found in five of 43 CRC tumor tissues. A higher cancer metastasis rate was uncovered in CRC patients with this mutation. The somatic mutations of APC gene may influence the clinical features of sporadic CRC. Arg1114X in APC gene, as a hot spot mutation in Chinese CRC, may predispose to the cancer metastasis of sporadic CRC.
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Affiliation(s)
- Xiaorong Liu
- Department of Genetics, Medical School, South East University, Nanjing, PR China
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Halberg RB, Waggoner J, Rasmussen K, White A, Clipson L, Prunuske AJ, Bacher JW, Sullivan R, Washington MK, Pitot HC, Petrini JHJ, Albertson DG, Dove WF. Long-lived Min mice develop advanced intestinal cancers through a genetically conservative pathway. Cancer Res 2009; 69:5768-75. [PMID: 19584276 DOI: 10.1158/0008-5472.can-09-0446] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
C57BL/6J mice carrying the Min allele of Adenomatous polyposis coli (Apc) develop numerous adenomas along the entire length of the intestine and consequently die at an early age. This short lifespan would prevent the accumulation of somatic genetic mutations or epigenetic alterations necessary for tumor progression. To overcome this limitation, we generated F(1) Apc(Min/+) hybrids by crossing C57BR/cdcJ and SWR/J females to C57BL/6J Apc(Min/+) males. These hybrids developed few intestinal tumors and often lived longer than 1 year. Many of the tumors (24-87%) were invasive adenocarcinomas, in which neoplastic tissue penetrated through the muscle wall into the mesentery. In a few cases (3%), lesions metastasized by extension to regional lymph nodes. The development of these familial cancers does not require chromosomal gains or losses, a high level of microsatellite instability, or the presence of Helicobacter. To test whether genetic instability might accelerate tumor progression, we generated Apc(Min/+) mice homozygous for the hypomorphic allele of the Nijmegen breakage syndrome gene (Nbs1(DeltaB)) and also treated Apc(Min/+) mice with a strong somatic mutagen. These imposed genetic instabilities did not reduce the time required for cancers to form nor increase the percentage of cancers nor drive progression to the point of distant metastasis. In summary, we have found that the Apc(Min/+) mouse model for familial intestinal cancer can develop frequent invasive cancers in the absence of overt genomic instability. Possible factors that promote invasion include age-dependent epigenetic changes, conservative somatic recombination, or direct effects of alleles in the F(1) hybrid genetic background.
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Affiliation(s)
- Richard B Halberg
- McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, Wisconsin 53706, USA
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Gómez-Fernández N, Castellví-Bel S, Fernández-Rozadilla C, Balaguer F, Muñoz J, Madrigal I, Milà M, Graña B, Vega A, Castells A, Carracedo A, Ruiz-Ponte C. Molecular analysis of the APC and MUTYH genes in Galician and Catalonian FAP families: a different spectrum of mutations? BMC MEDICAL GENETICS 2009; 10:57. [PMID: 19531215 PMCID: PMC2702373 DOI: 10.1186/1471-2350-10-57] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 06/16/2009] [Indexed: 12/28/2022]
Abstract
BACKGROUND Familial adenomatous polyposis (FAP) is an autosomal dominant-inherited colorectal cancer syndrome, caused by germline mutations in the APC gene. Recently, biallelic mutations in MUTYH have also been identified in patients with multiple colorectal adenomas and in APC-negative patients with FAP. The aim of this work is therefore to determine the frequency of APC and MUTYH mutations among FAP families from two Spanish populations. METHODS Eighty-two unrelated patients with classical or attenuated FAP were screened for APC germline mutations. MUTYH analysis was then conducted in those APC-negative families and in 9 additional patients from a previous study. Direct sequencing, SSCP analysis and TaqMan genotyping were used to identify point and frameshift mutations, meanwhile large rearrangements in the APC gene were screened by multiplex ligation-dependent probe amplification (MLPA). RESULTS APC germline mutations were found in 39% of the patients and, despite the great number of genetic variants described so far in this gene, seven new mutations were identified. The two hotspots at codons 1061 and 1309 of the APC gene accounted for 9,4% of the APC-positive families, although they were underrepresented in Galician samples. The deletion at codon 1061 was not found in 19 APC-positive Galician patients but represented 23% of the Catalonian positive families (p = 0,058). The same trend was observed at codon 1309, even though statistical analysis showed no significance between populations. Twenty-four percent of the APC-negative patients carried biallelic MUTYH germline mutations, and showed an attenuated polyposis phenotype generally without extracolonic manifestations. New genetic variants were found, as well as the two hotspots already reported (p.Tyr165Cys and p.Gly382Asp). CONCLUSION The results we present indicate that in Galician patients the frequency of the hotspot at codon 1061 in APC differs significantly from the Catalonian and also other Caucasian populations. Similar results had already been obtained in a previous study and could be due to the genetic isolation of the Galician population. MUTYH analysis is also recommended for all APC-negative families, even if a recessive inheritance is not confirmed.
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Affiliation(s)
- Nuria Gómez-Fernández
- Fundación Pública Galega de Medicina Xenómica, Grupo de Medicina Xenómica-USC, CIBERER, Santiago de Compostela, Galicia, Spain.
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Howarth K, Ranta S, Winter E, Teixeira A, Schaschl H, Harvey JJ, Rowan A, Jones A, Spain S, Clark S, Guenther T, Stewart A, Silver A, Tomlinson I. A mitotic recombination map proximal to the APC locus on chromosome 5q and assessment of influences on colorectal cancer risk. BMC MEDICAL GENETICS 2009; 10:54. [PMID: 19515250 PMCID: PMC2705358 DOI: 10.1186/1471-2350-10-54] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 06/10/2009] [Indexed: 11/10/2022]
Abstract
Background Mitotic recombination is important for inactivating tumour suppressor genes by copy-neutral loss of heterozygosity (LOH). Although meiotic recombination maps are plentiful, little is known about mitotic recombination. The APC gene (chr5q21) is mutated in most colorectal tumours and its usual mode of LOH is mitotic recombination. Methods We mapped mitotic recombination boundaries ("breakpoints") between the centromere (~50 Mb) and APC (~112 Mb) in early colorectal tumours. Results Breakpoints were non-random, with the highest frequency between 65 Mb and 75 Mb, close to a low copy number repeat region (68–71 Mb). There were, surprisingly, few breakpoints close to APC, contrary to expectations were there constraints on tumorigenesis caused by uncovering recessive lethal alleles or if mitotic recombination were mechanistically favoured by a longer residual chromosome arm. The locations of mitotic and meiotic recombination breakpoints were correlated, suggesting that the two types of recombination are influenced by similar processes, whether mutational or selective in origin. Breakpoints were also associated with higher local G+C content. The recombination and gain/deletion breakpoint maps on 5q were not, however, associated, perhaps owing to selective constraints on APC dosage in early colorectal tumours. Since polymorphisms within the region of frequent mitotic recombination on 5q might influence the frequency of LOH, we tested the 68–71 Mb low copy number repeat and nearby tagSNPs, but no associations with colorectal cancer risk were found. Conclusion LOH on 5q is non-random, but local factors do not greatly influence the rate of LOH at APC or explain inter differential susceptibility to colorectal tumours.
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Affiliation(s)
- Kimberley Howarth
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
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Learn PA, Kahlenberg MS. Hereditary colorectal cancer syndromes and the role of the surgical oncologist. Surg Oncol Clin N Am 2009; 18:121-44, ix. [PMID: 19056045 DOI: 10.1016/j.soc.2008.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The expanding understanding of the genetic basis to hereditary colon cancer syndromes is dismantling previously conceived categorizations and shedding light on why those schemes often failed in past. This review highlights evolving concepts regarding the genetic diagnosis and clinical management of the more commonly inherited colorectal cancer syndromes, including a discussion of recently described familial syndromes. This review also addresses clinician responsibilities in recognition of familial syndromes and provision of counseling.
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Affiliation(s)
- Peter A Learn
- Department of Surgery, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Kaufmann A, Vogt S, Uhlhaas S, Stienen D, Kurth I, Hameister H, Mangold E, Kötting J, Kaminsky E, Propping P, Friedl W, Aretz S. Analysis of rare APC variants at the mRNA level: six pathogenic mutations and literature review. J Mol Diagn 2009; 11:131-9. [PMID: 19196998 DOI: 10.2353/jmoldx.2009.080129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In monogenic disorders, the functional evaluation of rare, unclassified variants helps to assess their pathogenic relevance and can improve differential diagnosis and predictive testing. We characterized six rare APC variants in patients with familial adenomatous polyposis at the mRNA level. APC variants c.531 + 5G>C and c.532-8G>A in intron 4, c.1409-2_1409delAGG in intron 10, c.1548G>A in exon 11, and a large duplication of exons 10 and 11 result in a premature stop codon attributable to aberrant transcripts whereas the variant c.1742A>G leads to the in-frame deletion of exon 13 and results in the removal of a functional motif. Mutation c.1548G>A was detected in the index patient but not in his affected father, suggesting mutational mosaicism. A literature review shows that most of the rare APC variants detected by routine diagnostics and further analyzed at the transcript level were evaluated as pathogenic. The majority of rare APC variants, particularly those located close to exon-intron boundaries, could be classified as pathogenic because of aberrant splicing. Our study shows that the characterization of rare variants at the mRNA level is crucial for the evaluation of pathogenicity and underlying mutational mechanisms, and could lead to better treatment modalities.
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Lefevre JH, Parc Y, Svrcek M, Kernéis S, Colas C, Shields C, Flejou JF, Parc R, Tiret E. APC, MYH, and the correlation genotype-phenotype in colorectal polyposis. Ann Surg Oncol 2009; 16:871-7. [PMID: 19169759 DOI: 10.1245/s10434-008-0297-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 11/06/2008] [Accepted: 11/07/2008] [Indexed: 12/16/2022]
Abstract
BACKGROUND Familial adenomatous polyposis (FAP) has been divided into two entities: classical (CFAP) and attenuated (AFAP). With the discovery of MYH associated polyposis (MAP) syndrome, the clinical differences have become unclear. The aim of our study was to investigate patients with polyposis treated in our institution for a correlation between genotype and phenotype. METHODS Between 1978 and 2007, 515 patients were followed. Four groups were identified: AFAP, CFAP, MAP, and no-mutation patients. Clinical, surgical, histological, and genetic data of patients were collected and compared. Two ranges of mutations responsible for AFAP were used. RESULTS Patient breakdown was CFAP patients (n = 322/294), AFAP patients (n = 13/41), MYH patients (n = 17) and no-mut patients (n = 32). Patients not tested for APC mutation (n = 131) were excluded. Genotype/phenotype evaluation showed no difference in the number or location of polyps, age at colectomy, presence of cancer, or duodenal polyps. Major differences were found for MYH patients: later age at diagnosis, more cancers, fewer polyps, and more located in the right part of the colon. For phenotype/genotype correlation, patients aged more than 35 years at the time of colectomy and with fewer than 100 polyps had significantly more mutation found on MYH. CONCLUSIONS This two-way analysis did not show any correlation that might help to identify a subgroup of patients with APC mutation that may be considered attenuated. It is more likely that the MAP syndrome is the real AFAP.
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Affiliation(s)
- Jérémie H Lefevre
- Department of Digestive Surgery, Hopital Saint-Antoine, University Paris VII Pierre & Marie Curie, Paris, France.
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Nilbert M, Kristoffersson U, Ericsson M, Johannsson O, Rambech E, Mangell P. Broad phenotypic spectrum in familial adenomatous polyposis; from early onset and severe phenotypes to late onset of attenuated polyposis with the first manifestation at age 72. BMC MEDICAL GENETICS 2008; 9:101. [PMID: 19036155 PMCID: PMC2610029 DOI: 10.1186/1471-2350-9-101] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Accepted: 11/26/2008] [Indexed: 12/26/2022]
Abstract
Background Familial adenomatous polyposis (FAP) is typically characterized by multiple colonic polyps and frequent extracolonic features. Whereas the number of colonic polyps has been linked to the APC gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations. Methods Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify APC gene mutations, which were correlated to the clinical presentations. Results 10 novel APC gene mutations were identified in 11 families. A broad spectrum of extracolonic manifestations was identified in most of these individuals. Two sisters with an insertion in codon 528 (c.1582_1583insGC) both showed severe phenotypes with classical polyposis, upper gastrointestinal polyps and thyroid cancer. A woman with a 3'APC mutation (c.5030_5031insAA) developed colon cancer at age 72 as the first manifestation of attenuated FAP. Conclusion With an increasing number of FAP families diagnosed, a broad and variable tumor spectrum and a high frequency of extracolonic manifestations are gradually recognized. We report novel APC mutations and present two FAP cases that suggest familial aggregation of thyroid cancer and demonstrate the need to consider attenuated FAP also among elderly patients with colon cancer.
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Affiliation(s)
- Mef Nilbert
- Department of Oncology, Institute of Clinical Sciences, Lund University, Sweden.
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A large novel deletion in the APC promoter region causes gene silencing and leads to classical familial adenomatous polyposis in a Manitoba Mennonite kindred. Hum Genet 2008; 124:535-41. [PMID: 18982352 DOI: 10.1007/s00439-008-0579-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 10/21/2008] [Indexed: 11/26/2022]
Abstract
Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome caused by the inheritance of germline mutations in the APC tumour suppressor gene. The vast majority of these are nonsense and frameshift mutations resulting in a truncated protein product and abnormal function. While APC promoter hypermethylation has been previously documented, promoter-specific deletion mutations have not been reported. In a large Canadian Mennonite polyposis kindred, we identified a large novel germline deletion in the APC promoter region by linkage analysis and MLPA. By RT-PCR and sequence analysis, this mutation was found to result in transcriptional silencing of the APC allele. A few genetic disorders have been characterized as over-represented in the Manitoba Mennonite population, however, the incidence of cancer has not been recognized as increased in this population as compared to other Manitoba ethnic groups. This study strengthens the likelihood that this novel APC promoter mutation is linked to this unique population as a founder mutation.
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Segditsas S, Sieber OM, Rowan A, Setien F, Neale K, Phillips RKS, Ward R, Esteller M, Tomlinson IPM. Promoter hypermethylation leads to decreased APC mRNA expression in familial polyposis and sporadic colorectal tumours, but does not substitute for truncating mutations. Exp Mol Pathol 2008; 85:201-6. [PMID: 18977219 DOI: 10.1016/j.yexmp.2008.09.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 09/19/2008] [Indexed: 01/13/2023]
Abstract
Germline mutations in the tumour suppressor APC cause familial adenomatous polyposis (FAP), and somatic mutations are common in sporadic colorectal cancers (CRCs). Hypermethylation of APC promoter 1A has been reported in a substantial proportion of sporadic CRCs and may cause transcriptional silencing. Methylation has been proposed as an alternative to mutation or loss of heterozygosity as a mechanism of gene inactivation. However, the significance of APC methylation has remained unclear, because it has not previously been related to the presence of mono- or bi-allelic mutations at APC. We examined 103 FAP adenomas, 11 attenuated FAP adenomas, 31 sporadic CRCs and 30 CRC cell lines, all with known germline and/or somatic APC mutations. Overall, APC promoter 1A methylation was detected in 27-45% of colorectal tumours and cell lines, but generally not in histologically normal colorectum. In contrast to previous reports, methylation was detected in similar proportions of FAP/AFAP and sporadic CRCs. Importantly, methylation was independent of the presence, number and positions of APC mutations and was not associated with the CpG island methylator phenotype. Methylation resulted in a decrease or loss of 1A isoform mRNA and reduced total APC transcript levels, although expression was retained from promoter 1B. However, neither APC protein levels, nor transcription of a panel of Wnt target genes was associated with methylation status. Our data suggest that APC promoter 1A hypermethylation may influence APC expression levels in a subtle fashion, but methylation does not result in complete gene inactivation or act as a 'second hit'.
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Affiliation(s)
- Stefania Segditsas
- Molecular and Population Genetics Laboratory, London Research Institute, Cancer Research UK, London WC2A 3PX, UK
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Cheah PY. Recent advances in colorectal cancer genetics and diagnostics. Crit Rev Oncol Hematol 2008; 69:45-55. [PMID: 18774731 DOI: 10.1016/j.critrevonc.2008.08.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 07/11/2008] [Accepted: 08/13/2008] [Indexed: 12/12/2022] Open
Abstract
Colorectal cancer (CRC) is one of the most prevalent cancers and leading cause of cancer mortality worldwide. It is also one of the most curable cancers if detected early. This review classifies the diverse disease subtypes using various parameters including phenotypes of the polyps and describes how recent advances in genetics have impacted on disease diagnostics. For familial syndromes, the discovery of initiating mutations in the germline made personalized medicine a reality. A model linking the main tumorigenesis (Wnt/TGF-beta-BMP/LKB-1/PI3K-AKT) pathways and a strategy for gene testing are proposed. For sporadic CRC, high throughput technology has enabled the discovery of susceptibility loci that increased CRC risk. The ramifications of screening the population for susceptibility loci are discussed.
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Affiliation(s)
- Peh Yean Cheah
- Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Republic of Singapore.
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