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Akhlaghipour I, Bina AR, Abbaszadegan MR, Moghbeli M. Methylation as a critical epigenetic process during tumor progressions among Iranian population: an overview. Genes Environ 2021; 43:14. [PMID: 33883026 PMCID: PMC8059047 DOI: 10.1186/s41021-021-00187-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/07/2021] [Indexed: 11/10/2022] Open
Abstract
Cancer is one of the main health challenges and leading causes of deaths in the world. Various environmental and genetic risk factors are associated with tumorigenesis. Epigenetic deregulations are also important risk factors during tumor progression which are reversible transcriptional alterations without any genomic changes. Various mechanisms are involved in epigenetic regulations such as DNA methylation, chromatin modifications, and noncoding RNAs. Cancer incidence and mortality have a growing trend during last decades among Iranian population which are significantly related to the late diagnosis. Therefore, it is required to prepare efficient molecular diagnostic panels for the early detection of cancer in this population. Promoter hyper methylation is frequently observed as an inhibitory molecular mechanism in various genes associated with DNA repair, cell cycle regulation, and apoptosis during tumor progression. Since aberrant promoter methylations have critical roles in early stages of neoplastic transformations, in present review we have summarized all of the aberrant methylations which have been reported during tumor progression among Iranian cancer patients. Aberrant promoter methylations are targetable and prepare novel therapeutic options for the personalized medicine in cancer patients. This review paves the way to introduce a non-invasive methylation specific panel of diagnostic markers for the early detection of cancer among Iranians.
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Affiliation(s)
- Iman Akhlaghipour
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Reza Bina
- Student Research Committee, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | | | - Meysam Moghbeli
- Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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A decade in unravelling the etiology of gastric carcinogenesis in Kashmir, India – A high risk region. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Micronuclei Formation upon Radioiodine Therapy for Well-Differentiated Thyroid Cancer: The Influence of DNA Repair Genes Variants. Genes (Basel) 2020; 11:genes11091083. [PMID: 32957448 PMCID: PMC7565468 DOI: 10.3390/genes11091083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/07/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
Radioiodine therapy with 131I remains the mainstay of standard treatment for well-differentiated thyroid cancer (DTC). Prognosis is good but concern exists that 131I-emitted ionizing radiation may induce double-strand breaks in extra-thyroidal tissues, increasing the risk of secondary malignancies. We, therefore, sought to evaluate the induction and 2-year persistence of micronuclei (MN) in lymphocytes from 26 131I-treated DTC patients and the potential impact of nine homologous recombination (HR), non-homologous end-joining (NHEJ), and mismatch repair (MMR) polymorphisms on MN levels. MN frequency was determined by the cytokinesis-blocked micronucleus assay while genotyping was performed through pre-designed TaqMan® Assays or conventional PCR-restriction fragment length polymorphism (RFLP). MN levels increased significantly one month after therapy and remained persistently higher than baseline for 2 years. A marked reduction in lymphocyte proliferation capacity was also apparent 2 years after therapy. MLH1 rs1799977 was associated with MN frequency (absolute or net variation) one month after therapy, in two independent groups. Significant associations were also observed for MSH3 rs26279, MSH4 rs5745325, NBN rs1805794, and tumor histotype. Overall, our results suggest that 131I therapy may pose a long-term challenge to cells other than thyrocytes and that the individual genetic profile may influence 131I sensitivity, hence its risk-benefit ratio. Further studies are warranted to confirm the potential utility of these single nucleotide polymorphisms (SNPs) as radiogenomic biomarkers in the personalization of radioiodine therapy.
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Han Y, Peng Y, Fu Y, Cai C, Guo C, Liu S, Li Y, Chen Y, Shen E, Long K, Wang X, Yu J, Shen H, Zeng S. MLH1 Deficiency Induces Cetuximab Resistance in Colon Cancer via Her-2/PI3K/AKT Signaling. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000112. [PMID: 32670759 PMCID: PMC7341094 DOI: 10.1002/advs.202000112] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/29/2020] [Indexed: 05/13/2023]
Abstract
The rapid onset of resistance to cetuximab (CTX) limits its clinical utility in colorectal cancer (CRC) patients. This study aims to understand a potential role of mismatch repair gene mutL homolog 1 (MLH1) in CTX response. Functional analysis of MLH1 in Her-2/phosphoinositide 3-kinases (PI3K)/PKB protein kinase (AKT)-regulated CTX sensitivity is performed using human CRC specimens, CRC cell lines with different MLH1 expression levels, and a subcutaneous xenograft model. Overexpression, knockdown, small interfering RNA, and inhibitors are used to examine the role of MLH1 and HER-2 downstream signaling and apoptotic targets in CTX sensitivity. Reduced MLH1 expression is correlated with unfavorable prognosis in cetuximab-treated patients. MLH1 loss decreases CTX sensitivity through Her-2/PI3K/AKT signaling and apoptosis resistance in culture and in xenografts, while MLH1 overexpression increases CTX sensitivity. Blocking Her-2 signaling increases CTX sensitivity of microsatellite instability CRC in vitro and in vivo. MLH1 loss induces activation of Her-2/PI3K/AKT signaling and leads to cetuximab resistance in colon cancer.
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Affiliation(s)
- Ying Han
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPA15213USA
| | - Yinghui Peng
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Yaojie Fu
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Changjing Cai
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Cao Guo
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Shanshan Liu
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Yiyi Li
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Yihong Chen
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Edward Shen
- Department of Life ScienceMcMaster UniversityHamiltonONL8S 4L8Canada
| | - Kexin Long
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Xinwen Wang
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Jian Yu
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPA15213USA
| | - Hong Shen
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunan410008China
| | - Shan Zeng
- Department of OncologyXiangya HospitalCentral South UniversityChangshaHunan410008China
- Key Laboratory for Molecular Radiation Oncology of Hunan ProvinceXiangya HospitalCentral South UniversityChangshaHunan410008China
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Wang D, Zhang X, Zhang Y, Wu Y, Guan X, Zhu W, Wang M, Qi C, Shen B. Association of MLH1 single nucleotide polymorphisms with clinical outcomes of first-line irinotecan-based chemotherapy in colorectal cancer. Onco Targets Ther 2018; 11:8083-8088. [PMID: 30519050 PMCID: PMC6239120 DOI: 10.2147/ott.s180145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Several studies have proved that single nucleotide polymorphisms (SNPs) of mismatch repair system genes are closely related to the development of colorectal cancer (CRC) by causing microsatellite instability, while effects of the SNPs of MMR system-related genes on the clinical outcomes of cytotoxic chemotherapy are less understood. The aim of this study explored the influence of MLH1 SNPs on clinical outcomes of first-line irinotecan-based chemotherapy in CRC. PATIENTS AND METHODS A total of 125 metastatic colorectal cancer (mCRC) patients who received first-line irinotecan-based chemotherapy (none of them combined with bevacizumab or cetuximab) were enrolled in this study. Blood samples or formalin-fixed paraffin-embedded tissues of study population were taken. DNA isolation and genotyping analyzed were obtained for potential functional polymorphisms of MLH1 rs1800734 by real-time PCR. Progression-free survival (PFS) was the primary endpoint and tumor response rate (RR) was the secondary endpoint of this study. RESULTS Of all the assessable population, the result showed no statistical difference among the three types SNPs of MLH1 rs1800734 (AA, AG, GG) for RR (P=0.859), and also without significant difference for AA + AG combined variants vs GG variant (P=0.849). The median PFS for AA, AG, and GG variants of MLH1 rs1800734 SNPs were 9.4 months, 7.0 months, and 6.9 months, respectively (log-rank P=0.031). Interestingly, compared with AA variant of MLH1 rs1800734 SNPs, GG variant showed a shorter PFS (HR: 3.49; 95 CI: 1.02-11.94; P=0.046). Furthermore, the median PFS of AA + AG combined variants and GG variant were 8.3 months and 6.9 months (log-rank P=0.037), and GG variant have a decreased trend with no significant difference (HR: 1.57; 95 CI: 0.98-2.53; P=0.061). CONCLUSION The AA variant of MLH1 rs1800734 SNPs has a longer PFS in first-line irinotecan-based chemotherapy for mCRC patients, and the result needs to be further confirmed by prospective studies in the future.
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Affiliation(s)
- Deqiang Wang
- The Cancer Therapy Center, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Xiaomei Zhang
- Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China,
| | - Yan Zhang
- Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China,
| | - Yuan Wu
- Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China,
| | - Xin Guan
- Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China,
| | - Wei Zhu
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Mei Wang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Chuang Qi
- The Medical Department, 3D Medicines Inc., Shanghai, China
| | - Bo Shen
- Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China,
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Li S, Zheng Y, Tian T, Wang M, Liu X, Liu K, Zhai Y, Dai C, Deng Y, Li S, Dai Z, Lu J. Pooling-analysis on hMLH1 polymorphisms and cancer risk: evidence based on 31,484 cancer cases and 45,494 cancer-free controls. Oncotarget 2017; 8:93063-93078. [PMID: 29190978 PMCID: PMC5696244 DOI: 10.18632/oncotarget.21810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/08/2017] [Indexed: 01/18/2023] Open
Abstract
To elucidate the veritable relationship between three hMLH1 polymorphisms (rs1800734, rs1799977, rs63750447) and cancer risk, we performed this meta-analysis based on overall published data up to May 2017, from PubMed, Web of knowledge, VIP, WanFang and CNKI database, and the references of the original studies or review articles. 57 publications including 31,484 cancer cases and 45,494 cancer-free controls were obtained. The quality assessment of six articles obtained a summarized score less than 6 in terms of the Newcastle-Ottawa Scale (NOS). All statistical analyses were calculated with the software STATA (Version 14.0; Stata Corp, College Station, TX). We found all the three polymorphisms can enhance overall cancer risk, especially in Asians, under different genetic comparisons. In the subgroup analysis by cancer type, we found a moderate association between rs1800734 and the risk of gastric cancer (allele model: OR = 1.14, P = 0.017; homozygote model: OR = 1.33, P = 0.019; dominant model: OR = 1.27, P = 0.024) and lung cancer in recessive model (OR = 1.27, P = 0.024). The G allele of rs1799977 polymorphism was proved to connect with susceptibility of colorectal cancer (allele model: OR = 1.21, P = 0.023; dominate model: OR = 1.32, P <0.0001) and prostate cancer (dominate model: OR = 1.36, P <0.0001). Rs63750447 showed an increased risk of colorectal cancer, endometrial cancer and gastric cancer under all genetic models. These findings provide evidence that hMLH1 polymorphisms may associate with cancer risk, especially in Asians.
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Affiliation(s)
- Sha Li
- Clinical Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China.,Department of Pharmacy, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yi Zheng
- Clinical Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China.,Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Tian Tian
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Meng Wang
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Xinghan Liu
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Kang Liu
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yajing Zhai
- Clinical Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Cong Dai
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yujiao Deng
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Shanli Li
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Zhijun Dai
- Department of Oncology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Jun Lu
- Clinical Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
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Single-Nucleotide Polymorphisms of the MSH2 and MLH1 Genes, Potential Molecular Markers for Susceptibility to the Development of Basal Cell Carcinoma in the Brazilian Population. Pathol Oncol Res 2017; 24:489-496. [DOI: 10.1007/s12253-017-0265-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/21/2017] [Indexed: 12/15/2022]
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Hsieh YC, Cho EC, Tu SH, Wu CH, Hung CS, Hsieh MC, Su CT, Liu YR, Lee CH, Ho YS, Chiou HY. MSH2 rs2303425 Polymorphism is Associated with Early-Onset Breast Cancer in Taiwan. Ann Surg Oncol 2016; 24:603-610. [DOI: 10.1245/s10434-016-5168-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Indexed: 11/18/2022]
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Zhu H, Li X, Zhang X, Chen D, Li D, Ren J, Gu H, Shu Y, Wang D. Polymorphisms in mismatch repair genes are associated with risk and microsatellite instability of gastric cancer, and interact with life exposures. Gene 2016; 579:52-7. [DOI: 10.1016/j.gene.2015.12.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 12/04/2015] [Accepted: 12/22/2015] [Indexed: 12/11/2022]
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Liu L, Yang X. Implication of Reprimo and hMLH1 gene methylation in early diagnosis of gastric carcinoma. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:14977-14982. [PMID: 26823831 PMCID: PMC4713617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/21/2015] [Indexed: 06/05/2023]
Abstract
DNA methylation has been recently recognized as a novel tumor marker. This study investigated the methylation status of Reprimo and hMLH1 gene in both plasma and tissue samples from gastric cancer patients, in an attempt to investigate their diagnostic implications in gastric cancer. A total of 180 tissue and plasma samples (including 50 cases of gastric cancer, 50 dysplasia, 50 chronic atrophic gastritis with intestinal metaplasia and 30 normal controls) were collected for detecting DNA methylation status of Reprimo and hMLH1 genes using MSP method. Tissue protein expression levels were further tested by immunohistochemical (IHC) staining. The positive rate of DNA methylation rate was, in ascending sequence, gastritis tissue, dysplasia tissue and gastric carcinoma tissue. All those tissues had significantly elevated DNA methylation level compared to normal group (P < 0.05). Expression level of Reprimo and hMLH1 proteins were, however, decreased in pathological tissues compared to normal ones (P < 0.05). A significantly negative relationship existed between protein level and promoter region methylation level. The DNA methylation occurred in promoter regions of both Reprimo and hMLH1 genes depressed the protein expression, and may participate in the occurrence and progression and gastric cancer. The combined assay of serum Reprimo and hMLH1 DNA methylation levels thus had critical importance in the early diagnosis and gastric cancer.
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Affiliation(s)
- Lianhua Liu
- Department of Radiotherapy, Lin-Yi Cancer HospitalLinyi 276001, Shangdong, China
| | - Xiaofeng Yang
- Department of Emergency Surgery, Lin-Yi People’s HospitalLinyi 276001, Shandong, China
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Hudler P. Challenges of deciphering gastric cancer heterogeneity. World J Gastroenterol 2015; 21:10510-10527. [PMID: 26457012 PMCID: PMC4588074 DOI: 10.3748/wjg.v21.i37.10510] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 06/19/2015] [Accepted: 08/31/2015] [Indexed: 02/06/2023] Open
Abstract
Gastric cancer is in decline in most developed countries; however, it still accounts for a notable fraction of global mortality and morbidity related to cancer. High-throughput methods are rapidly changing our view and understanding of the molecular basis of gastric carcinogenesis. Today, it is widely accepted that the molecular complexity and heterogeneity, both inter- and intra-tumour, of gastric adenocarcinomas present significant obstacles in elucidating specific biomarkers for early detection of the disease. Although genome-wide sequencing and gene expression studies have revealed the intricate nature of the molecular changes that occur in tumour landscapes, the collected data and results are complex and sometimes contradictory. Several aberrant molecules have already been tested in clinical trials, although their diagnostic and prognostic utilities have not been confirmed thus far. The gold standard for the detection of sporadic gastric cancer is still the gastric endoscopy, which is considered invasive. In addition, genome-wide association studies have confirmed that genetic variations are important contributors to increased cancer risk and could participate in the initiation of malignant transformation. This hypothesis could in part explain the late onset of sporadic gastric cancers. The elaborate interplay of polymorphic low penetrance genes and lifestyle and environmental risk factors requires additional research to decipher their relative impacts on tumorigenesis. The purpose of this article is to present details of the molecular heterogeneity of sporadic gastric cancers at the DNA, RNA, and proteome levels and to discuss issues relevant to the translation of basic research data to clinically valuable tools. The focus of this work is the identification of relevant molecular changes that could be detected non-invasively.
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Ahmad M, Tuteja R. Emerging importance of mismatch repair components including UvrD helicase and their cross-talk with the development of drug resistance in malaria parasite. Mutat Res 2014; 770:54-60. [PMID: 25771870 DOI: 10.1016/j.mrfmmm.2014.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 08/14/2014] [Accepted: 09/17/2014] [Indexed: 06/04/2023]
Abstract
Human malaria is an important parasitic infection responsible for a significant number of deaths worldwide, particularly in tropical and subtropical regions. The recent scenario has worsened mainly because of the emergence of drug-resistant malaria parasites having the potential to spread across the world. Drug-resistant parasites possess a defective mismatch repair (MMR); therefore, it is essential to explore its mechanism in detail to determine the underlying cause. Recently, artemisinin-resistant parasites have been reported to exhibit nonsynonymous single nucleotide polymorphisms in genes involved in MMR pathways such as MutL homolog (MLH) and UvrD. Plasmodium falciparum MLH is an endonuclease required to restore the defective MMR in drug-resistant W2 strain of P. falciparum. Although the role of helicases in eukaryotic MMR has been questioned, the identification and characterization of the UvrD helicase and their cross-talk with MLH in P. falciparum suggests the possible involvement of UvrD in MMR. A comparative genome-wide analysis revealed the presence of the UvrD helicase in Plasmodium species, while it is absent in human host. Therefore, PfUvrD may emerge as a suitable drug target to control malaria. This review study is focused on recent developments in MMR biochemistry, emerging importance of the UvrD helicase, possibility of its involvement in MMR and the emerging cross-talk between MMR components and drug resistance in malaria parasite.
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Affiliation(s)
- Moaz Ahmad
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Renu Tuteja
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India.
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Moghbeli M, Moaven O, Memar B, Raziei HR, Aarabi A, Dadkhah E, Forghanifard MM, Manzari F, Abbaszadegan MR. Role of hMLH1 and E-cadherin promoter methylation in gastric cancer progression. J Gastrointest Cancer 2014; 45:40-7. [PMID: 24022108 DOI: 10.1007/s12029-013-9548-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Gastric cancer (GC) is one of the leading causes of cancer-related death in Iran. Genome stability is one of the main genetic issues in cancer biology which is governed via the different repair systems such as DNA mismatch repair (MMR). A clear correlation between MMR defects and tumor progression has been shown. Beside the genetic mutations, epigenetic changes also have a noticeable role in MMR defects. METHODS Here, we assessed promoter methylation status and the level of hMLH1mRNA expression as the main component of MMR system in 51 GC patients using the methylation-specific PCR and real-time PCR, respectively. Moreover, we performed a promoter methylation study of the E-cadherin gene promoter. RESULTS It was observed that, 12 out of 39 cases (23.5%) had hMLH1 overexpression. Hypermethylation of hMLH1 and E-cadherin promoter regions were observed in 25.5 and 36.4%, respectively. Although, there was no significant correlation between hMLH1 mRNA expression and clinicopathological features, there are significant correlations between E-cadherin promoter methylation and tumor stage (p = 0.028) and location (p = 0.025). The rate of hMLH1 promoter methylation in this study was lower than that in the other population, showing the importance of the other mechanisms, in gastric tumorigenesis. CONCLUSION The results of this study indicate that DNA repair system is adversely affected by hypermethylation of hMLH1 in a fraction of gastric cancer patients. Additionally, E-cadherin hypermethylation seen in a subset of our gastric cancer patients is consistent with other reports showing correlation with aggressiveness and metastasis of gastric cancer.
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Affiliation(s)
- Meysam Moghbeli
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran
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