Genetic testing for inherited colon cancer

Effect of genetic profiling on surgical decisions at hereditary colorectal cancer syndromes

Hereditary colorectal cancer syndromes, such as Lynch syndrome and familial adenomatous polyposis (FAP), present significant clinical challenges due to the heightened cancer risks associated with these genetic conditions. This review explores genetic profiling impact on surgical decisions for hereditary colorectal cancer (HCRC), assessing options, timing, and outcomes. Genotypes of different HCRCs are discussed, revealing a connection between genetic profiles, disease severity, and outcomes. For Lynch syndrome, mutations in the MLH1, MSH2, MSH6, and PMS2 genes guide the choice of surgery. Subtotal colectomy is recommended for patients with mutations in MLH1 and MSH2, while segmental colectomy is preferred for those with MSH6 and PMS2 mutations. In cases of metachronous colon cancer after segmental colectomy, subtotal colectomy with ileorectal anastomosis is advised for all mutations. Surgical strategies for primary rectal cancer include anterior resection or abdominoperineal resection (APR), irrespective of the specific mutation. For rectal cancer occurring after a previous segmental colectomy, proctocolectomy with ileal pouch-anal anastomosis (IPAA) or APR with a permanent ileostomy is recommended. In FAP, surgical decisions are based on genotype-phenotype correlations. The risk of desmoid tumors post-surgery supports a single-stage approach, particularly for certain APC gene variants. Juvenile Polyposis Syndrome (JPS) surgical decisions involve genetic testing, polyp characteristics with attention to vascular lesions in SMAD4 mutation carriers. However, genetic profiling does not directly dictate the specific surgical approach for JPS. In conclusion this review highlights the critical role of personalized surgical plans based on genetic profiles to optimize patient outcomes and reduce cancer risk. Further research is needed to refine these strategies and enhance clinical guidelines.

Hereditary Colorectal Cancer Syndromes Registry: What, How, and Why?

Caring for patients with colorectal cancer inherited cancer syndromes is complex, and it requires a well-thought integration process between a multidisciplinary team, an accessible database, and a registry coordinator. This requires an aligned vision between the administrative business team and the clinical team. Although we can manage most of the cancers that those patients develop according to oncologic guidance, the future risk of patients and their families might add emotional and psychological burdens on them in the absence of a well-qualified and trained team where balancing quality of life and cancer risk are at the essence of decision making.

The evolution of informed consent in gastroenterology

With medical litigation on the rise, physicians require a nuanced understanding of the legalities of consenting patients to reduce their liability while practising evidence-based medicine. This study aims to a) clarify the legal duties of gastroenterologists in the UK and USA when gaining informed consent and b) provide recommendations at the international and physician level to improve the consent process and reduce liability.A bibliometric analysis of the Web of Science database with the MeSH terms "gastroenterology" and "informed consent" yielded 383 articles, of which 228 were excluded due to not meeting the inclusion criteria. Of the top 50 articles, 48% were from American institutions and 16% were from the UK. Thematic analysis showed 72% of the articles discussed informed consent in relation to diagnostic procedures, 14% regarding treatment, and 14% regarding research participation.Both the USA and the UK have progressed from previously paternalistic Natanson case (1960) and Bolam test (1957), respectively, where physicians were held to the standard of a "reasonable and prudent medical doctor". The American Canterbury case (1972) and the British Montgomery case (2015) radically shifted the standard of disclosure during the consent process by requiring physicians to explain all information pertinent to a "reasonable patient".It is our recommendation that a two-pronged approach be taken; a) creation of international guidelines for consenting patients for invasive procedures in gastroenterology, and b) development of internationally standardised endoscopy consent forms containing all the details pertinent to a "reasonable patient".

AGA Clinical Practice Update on Risk Stratification for Colorectal Cancer Screening and Post-Polypectomy Surveillance: Expert Review

DESCRIPTION

Since the early 2000s, there has been a rapid decline in colorectal cancer (CRC) mortality, due in large part to screening and removal of precancerous polyps. Despite these improvements, CRC remains the second leading cause of cancer deaths in the United States, with approximately 53,000 deaths projected in 2023. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update Expert Review was to describe how individuals should be risk-stratified for CRC screening and post-polypectomy surveillance and to highlight opportunities for future research to fill gaps in the existing literature.

METHODS

This Expert Review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. These Best Practice Advice statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: All individuals with a first-degree relative (defined as a parent, sibling, or child) who was diagnosed with CRC, particularly before the age of 50 years, should be considered at increased risk for CRC. BEST PRACTICE ADVICE 2: All individuals without a personal history of CRC, inflammatory bowel disease, hereditary CRC syndromes, other CRC predisposing conditions, or a family history of CRC should be considered at average risk for CRC. BEST PRACTICE ADVICE 3: Individuals at average risk for CRC should initiate screening at age 45 years and individuals at increased risk for CRC due to having a first-degree relative with CRC should initiate screening 10 years before the age at diagnosis of the youngest affected relative or age 40 years, whichever is earlier. BEST PRACTICE ADVICE 4: Risk stratification for initiation of CRC screening should be based on an individual's age, a known or suspected predisposing hereditary CRC syndrome, and/or a family history of CRC. BEST PRACTICE ADVICE 5: The decision to continue CRC screening in individuals older than 75 years should be individualized, based on an assessment of risks, benefits, screening history, and comorbidities. BEST PRACTICE ADVICE 6: Screening options for individuals at average risk for CRC should include colonoscopy, fecal immunochemical test, flexible sigmoidoscopy plus fecal immunochemical test, multitarget stool DNA fecal immunochemical test, and computed tomography colonography, based on availability and individual preference. BEST PRACTICE ADVICE 7: Colonoscopy should be the screening strategy used for individuals at increased CRC risk. BEST PRACTICE ADVICE 8: The decision to continue post-polypectomy surveillance for individuals older than 75 years should be individualized, based on an assessment of risks, benefits, and comorbidities. BEST PRACTICE ADVICE 9: Risk-stratification tools for CRC screening and post-polypectomy surveillance that emerge from research should be examined for real-world effectiveness and cost-effectiveness in diverse populations (eg, by race, ethnicity, sex, and other sociodemographic factors associated with disparities in CRC outcomes) before widespread implementation.

Clinical Multigene Panel Testing Identifies Racial and Ethnic Differences in Germline Pathogenic Variants Among Patients With Early-Onset Colorectal Cancer

PURPOSE

The early-onset colorectal cancer (EOCRC) burden differs across racial/ethnic groups, yet the role of germline genetic predisposition in EOCRC disparities remains uncharacterized. We defined the prevalence and spectrum of inherited colorectal cancer (CRC) susceptibility gene variations among patients with EOCRC by race and ethnicity.

PATIENTS AND METHODS

We included individuals diagnosed with a first primary CRC between age 15 and 49 years who identified as Ashkenazi Jewish, Asian, Black, Hispanic, or White and underwent germline genetic testing of 14 CRC susceptibility genes performed by a clinical testing laboratory. Variant comparisons by racial and ethnic groups were evaluated using chi-square tests and multivariable logistic regression adjusted for sex, age, CRC site, and number of primary colorectal tumors.

RESULTS

Among 3,980 patients with EOCRC, a total of 530 germline pathogenic or likely pathogenic variants were identified in 485 individuals (12.2%). By race/ethnicity, 12.7% of Ashkenazim patients, 9.5% of Asian patients, 10.3% of Black patients, 14.0% of Hispanic patients, and 12.4% of White patients carried a germline variant. The prevalence of Lynch syndrome (P = .037), as well as APC, CHEK2, MLH1, monoallelic MUTYH, and PTEN variants, varied by race/ethnicity among patients with EOCRC (all P < .026). Ashkenazim and Hispanic patients had significantly higher odds of presenting with a pathogenic APC variant, which included p.I1307K (odds ratio [OR], 2.67; 95% CI, 1.30 to 5.49; P = .007) and MLH1 variant (OR, 8.69; 95% CI, 2.68 to 28.20; P = .0003), respectively, versus White patients in adjusted models.

CONCLUSION

Germline genetic features differed by race/ethnicity in young patients with CRC, suggesting that current multigene panel tests may not be representative of EOCRC risk in diverse populations. Further study is needed to optimize genes selected for genetic testing in EOCRC via ancestry-specific gene and variant discovery to yield equitable clinical benefits for all patients and to mitigate inequities in disease burden.

Genetic Predisposition to Colorectal Cancer: How Many and Which Genes to Test?

Colorectal cancer is one of the most common tumors, and genetic predisposition is one of the key risk factors in the development of this malignancy. Lynch syndrome and familial adenomatous polyposis are the best-known genetic diseases associated with hereditary colorectal cancer. However, some other genetic disorders confer an increased risk of colorectal cancer, such as Li-Fraumeni syndrome (TP53 gene), MUTYH-associated polyposis (MUTYH gene), Peutz-Jeghers syndrome (STK11 gene), Cowden syndrome (PTEN gene), and juvenile polyposis syndrome (BMPR1A and SMAD4 genes). Moreover, the recent advances in molecular techniques, in particular Next-Generation Sequencing, have led to the identification of many new genes involved in the predisposition to colorectal cancers, such as RPS20, POLE, POLD1, AXIN2, NTHL1, MSH3, RNF43 and GREM1. In this review, we summarized the past and more recent findings in the field of cancer predisposition genes, with insights into the role of the encoded proteins and into the associated genetic disorders. Furthermore, we discussed the possible clinical utility of genetic testing in terms of prevention protocols and therapeutic approaches.

Oncology Informatics for Lynch Syndrome Research and Care: A Literature Review

PURPOSE

This study aims to review and evaluate available informatics platforms for research and management purposes of Lynch syndrome (LS) to identify gaps and needs for future development.

METHODS

LS informatics tools were identified through literature search in four publication databases (1 and Scopus). First, the LS and functional elements of every informatics tools for LS were introduced. Then, current existing LS informatics tools were reviewed and explained.

RESULTS

A detailed review of implemented studies shows that many types of informatics platforms are available for LS management (ie, prediction model, clinical decision support system, database website, and other tools for research and management purposes of LS). Moreover, several dimensions of existing LS informatics tools were discussed and features and positive findings were reported.

CONCLUSION

Reviewing the literature reveals that several LS informatics tools were focused on gene-specific estimate, cancer risk prediction, identifying/screening patients, supporting personalized care of individuals with LS, and storing mismatch repair mutations information. Nevertheless, these platforms do not fully cover the care and research purposes. For instance, future developments of LS tools require more attention to dynamic knowledgebase, extra-colonic lynch–related cancers on the basis of precision medicine, variants of unknown significance, and support from diagnosis to surveillance for patient follow-up. Insights and recommendations provided in this study could help researchers and developers to meet the existing challenges in future developments.

Approach to Familial Predisposition to Colorectal Cancer

The traditional approach of one-size-fits-all for colorectal cancer has been replaced by personalized interventions to an individual's unique genetic, molecular, and environmental profile, seeking to identify high-risk individuals who would benefit from individualized screening and surveillance. This change in approach is due, in part, to emerging technologies, such as next-generation DNA sequencing.

SEOM-GETTHI clinical guideline for the practical management of molecular platforms (2021)

The improvement of molecular alterations in cancer as well as the development of technology has allowed us to bring closer to clinical practice the determination of molecular alterations in the diagnosis and treatment of cancer. The use of multidetermination platforms is spreading in most Spanish hospitals. The objective of these clinical practice guides is to review their usefulness, and establish usage guidelines that guide their incorporation into clinical practice.

Novel Methylation Biomarkers for Colorectal Cancer Prognosis

Colorectal cancer (CRC) comprises the third most common cancer worldwide and the second regarding number of deaths. In order to make a correct and early diagnosis to predict metastasis formation, biomarkers are an important tool. Although there are multiple signaling pathways associated with cancer progression, the most recognized are the MAPK pathway, p53 pathway, and TGF-β pathway. These pathways regulate many important functions in the cell, such as cell cycle regulation, proliferation, differentiation, and metastasis formation, among others. Changes in expression in genes belonging to these pathways are drivers of carcinogenesis. Often these expression changes are caused by mutations; however, epigenetic changes, such as DNA methylation, are increasingly acknowledged to play a role in the deregulation of oncogenic genes. This makes DNA methylation changes an interesting biomarkers in cancer. Among the newly identified biomarkers for CRC metastasis INHBB, SMOC2, BDNF, and TBRG4 are included, all of which are highly deregulated by methylation and closely associated with metastasis. The identification of such biomarkers in metastasis of CRC may allow a better treatment and early identification of cancer formation in order to perform better diagnostics and improve the life expectancy.

Precision medicine for hereditary tumors in gynecologic malignancies

Genomic medicine for gynecologic tumors is characterized by hereditary breast and ovarian cancer (HBOC) and Lynch syndrome (LS). Poly ADP-ribose polymerase (PARP) inhibitor, olaparib, and the immune checkpoint inhibitor, pembrolizumab, which are drugs that show sensitivity to each hereditary tumor, have begun to spread in clinical practice for gynecologic malignancies. In clinical use, platinum sensitivity is used as a clinical surrogate marker for olaparib sensitivity, and microsatellite instability is used as a biological surrogate marker for pembrolizumab sensitivity. BRCA genetic testing and microsatellite instability test have been used as companion diagnostics before starting olaparib and pembrolizumab treatment, respectively. Homologous recombination deficiency test could be used for companion diagnostic of olaparib combination with bevacizumab in first-line maintenance treatment and niraparib without re-administration of platinum agents in the treatment of recurrence. The approval of the three drugs has been changing the treatment of gynecologic malignancies. Furthermore, preventive medical care has been covered by insurance since April 2020 for breast and/or ovarian cancer patients with germline BRCA1/2 mutation in Japan. This review article outlines the current status and future prospects of precision medicine for gynecologic hereditary tumors focusing on HBOC and LS.

Feature Selection for Colon Cancer Detection Using K-Means Clustering and Modified Harmony Search Algorithm

This paper proposes a feature selection method that is effective in distinguishing colorectal cancer patients from normal individuals using K-means clustering and the modified harmony search algorithm. As the genetic cause of colorectal cancer originates from mutations in genes, it is important to classify the presence or absence of colorectal cancer through gene information. The proposed methodology consists of four steps. First, the original data are Z-normalized by data preprocessing. Candidate genes are then selected using the Fisher score. Next, one representative gene is selected from each cluster after candidate genes are clustered using K-means clustering. Finally, feature selection is carried out using the modified harmony search algorithm. The gene combination created by feature selection is then applied to the classification model and verified using 5-fold cross-validation. The proposed model obtained a classification accuracy of up to 94.36%. Furthermore, on comparing the proposed method with other methods, we prove that the proposed method performs well in classifying colorectal cancer. Moreover, we believe that the proposed model can be applied not only to colorectal cancer but also to other gene-related diseases.

Genetic Testing and Screening Recommendations for Patients with Hereditary Breast Cancer

Professionals who specialize in breast imaging may be the first to initiate the conversation about genetic counseling with patients who have a diagnosis of premenopausal breast cancer or a strong family history of breast and ovarian cancer. Commercial genetic testing panels have gained popularity and have become more affordable in recent years. Therefore, it is imperative for radiologists to be able to provide counseling and to identify those patients who should be referred for genetic testing. The authors review the process of genetic counseling and the associated screening recommendations for patients at high and moderate risk. Ultimately, genetic test results enable appropriate patient-specific screening, which allows improvement of overall survival by early detection and timely treatment. The authors discuss pretest counseling, which involves the use of various breast cancer risk assessment tools such as the Gail and Tyrer-Cuzick models. The most common high- and moderate-risk gene mutations associated with breast cancer are also reviewed. In addition to BRCA1 and BRCA2, several high-risk genes, including TP53, PTEN, CDH1, and STK11, are discussed. Moderate-risk genes include ATM, CHEK2, and PALB2. The imaging appearances of breast cancer typically associated with each gene mutation, as well as the other associated cancers, are described. ^©RSNA, 2020 See discussion on this article by Butler (pp 937-940).

Use of Family History and Genetic Testing to Determine Risk of Colorectal Cancer

Approximately 35% of patients with colorectal cancer (CRC) have a family history of the disease attributed to genetic factors, common exposures, or both. Some families with a history of CRC carry genetic variants that cause CRC with high or moderate penetrance, but these account for only 5% to 10% of CRC cases. Most families with a history of CRC and/or adenomas do not carry genetic variants associated with cancer syndromes; this is called common familial CRC. Our understanding of familial predisposition to CRC and cancer syndromes has increased rapidly due to advances in next-generation sequencing technologies. As a result, there has been a shift from genetic testing for specific inherited cancer syndromes based on clinical criteria alone, to simultaneous testing of multiple genes for cancer-associated variants. We summarize current knowledge of common familial CRC, provide an update on syndromes associated with CRC (including the nonpolyposis and polyposis types), and review current recommendations for CRC screening and surveillance. We also provide an approach to genetic evaluation and testing in clinical practice. Determination of CRC risk based on family cancer history and results of genetic testing can provide a personalized approach to cancer screening and prevention, with optimal use of colonoscopy to effectively decrease CRC incidence and mortality.

Outcome of thyroid ultrasound screening in FAP patients with a normal baseline exam

Familial adenomatous polyposis (FAP) is a hereditary cancer syndrome associated with a substantial lifetime risk for colorectal cancer. The leading extra-colonic causes of cancer in FAP include duodenal and thyroid cancer (TC). Recent guidelines recommend annual thyroid ultrasound (TUS) screening beginning in the teenage years but the evidence to support the interval particularly in FAP patients with a normal baseline ultrasound is lacking. TUS results from FAP patients enrolled in a thyroid screening program from 2006 to 2016 and who had at least 2 TUS were reviewed. TUS findings were classified as normal, low (LR) or high risk (HR) for TC based on nodule characteristics as determined by American Thyroid Association (ATA) guidelines. We assessed the incidence of TC in patient with normal baseline TUS and factors associated with TC. 264 FAP patients were included. Baseline TUS was normal in 167, LR in 74, and HR in 24 patients. Patients were observed for a mean 4.8 years and underwent an average of 3 TUS. Patients with normal baseline TUS did not develop TC during the course of follow up of 5.1 years. TC developed in 6 patients (2.3%) all with baseline nodules; 5 in the LR group and 1 in the HR group. Factors associated with development of TC were presence of baseline nodule(s) and female sex. The development of TC in FAP patients in a TUS screening program with short term follow up is low and no FAP patient with a normal baseline TUS developed TC during observation. Annual TUS in patients with a normal baseline TUS may not be needed. Extending the screening interval to 2 years may be reasonable until nodules are detected.

Management of Juvenile Polyposis Syndrome in Children and Adolescents: A Position Paper From the ESPGHAN Polyposis Working Group

The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Polyposis Working Group developed recommendations to assist clinicians and health care providers with appropriate management of patients with juvenile polyposis. This is the first juvenile polyposis Position Paper published by ESPGHAN with invited experts. Many of the published studies were descriptive and/or retrospective in nature, consequently after incorporating a modified version of the GRADE system many of the recommendations are based on expert opinion. This ESPGHAN Position Paper provides a guide for diagnosis, assessment, and management of juvenile polyposis syndrome in children and adolescents, and will be helpful in the appropriate management and timing of procedures in children and adolescents. The formation of international collaboration and consortia is proposed to monitor patients prospectively to advance our understanding of juvenile polyposis conditions.

Natural history of colonic polyposis in young patients with familial adenomatous polyposis

BACKGROUND AND AIMS

Proctocolectomy prevents colorectal cancer in familial adenomatous polyposis (FAP). Colorectal polyp progression is one of the indications for surgery. No data exist regarding the natural history of colorectal polyposis in young patients with FAP. This study examined the rate of polyposis progression and factors associated with it.

METHODS

Patients with FAP <30 years old who had undergone ≥2 colonoscopies since 2000 were identified. Rate of polyposis progression was calculated by review of polyp counts obtained from baseline and last colonoscopy, accounting for any polyps removed during the observation period. Endoscopic and non-endoscopic factors affecting the rate of polyposis progression were evaluated. Multivariate analysis was performed to identify factors associated with rate of polyposis progression.

RESULTS

One hundred sixty-eight patients (52% female; median age, 13.5 years) were included. Median rate of polyposis progression was 25.4 polyps/year (interquartile range, 9.5-69.8). Highest median rate of polyposis progression (89 polyps/year) was associated with mutation in codon 1309. The rate of polyposis progression was independently associated with the location of mutation in the adenomatous polyposis coli gene, the number of polyps at the initial colonoscopy, and exposure to chemoprevention. Of the 39.9% of patients who underwent surgery, an increase in polyp number was the most common indication (53.7%).

CONCLUSIONS

The rate of polyposis progression in young patients with FAP varies with a median of about 25 new polyps per year. Progression is associated with distinct factors, which can be used in discussion with patients regarding the need for and timing of prophylactic colorectal surgery.

Integrating surgery and genetic testing for the modern surgeon

The field of cancer genetics is rapidly evolving and several genetic mutations have been identified in hereditary cancer syndromes. These mutations can be diagnosed via routine genetic testing allowing prompt intervention. This is especially true for certain variants of colorectal, breast, and thyroid cancers where genetic testing may guide surgical therapy. Ultimately, surgical intervention may drastically diminish disease manifestation or progression in individuals deemed as high-risk based on their genetic makeup. Understanding the concepts of gene-based testing and integrating into current surgical practice is crucial. This review addresses common genetic syndromes, tests, and interventions salient to the current surgeon.

Hereditary or sporadic polyposis syndromes

Polyposis syndromes are encountered in endoscopy practice, and are considered rare entities, accounting for ≤1% of colorectal cancer. Polyposis can occur within inherited syndromes or as "sporadic" cases of unknown etiology. Their proper characterization is relevant for patient management, and should nowadays drive appropriate genetic tests which have a key role in clinical practice for driving surveillance and colorectal cancer prevention, enlarged to relatives. Polyposis classification is based upon polyp number and histology, familial and personal history. This review will explore the polyposis nosology and their genetic determinants in the emerging scenario of Next Generation Sequencing which allow testing multiples genes in parallel. This capability will likely continue to increase the range of polyposis predisposing genes, contributing to define new clinical entities.

Hereditary Colorectal Cancer Syndromes

Awareness of hereditary colorectal cancer syndromes is important to facilitate their identification because affected patients are at increased risk for early onset, synchronous, and metachronous colorectal malignancies, and certain extracolonic malignancies depending on the syndrome. Identification of an affected individual allows for screening and early interventions for patients and their at-risk kindred. Genetic counseling and testing is important to the care of these patients. As knowledge of the genetic basis of these syndromes grows, unique genotype-phenotype profiles allow clinicians to tailor surveillance and treatment strategies based on individual risk.

Are We Overdoing Pediatric Lower Gastrointestinal Endoscopy?

INTRODUCTION

Lower gastrointestinal endoscopy (LGIE)/colonoscopy is frequently performed for rectal bleeding, recurrent abdominal pain, and the diagnosis of inflammatory bowel disease (IBD). Although these are common indications, the causes of isolated rectal bleeding and recurrent abdominal pain in the otherwise well child have not been described.

METHODS

A retrospective analysis of patients who had had an LGIE/colonoscopy from January 2001 to December 2010 was performed. The following data were collected: demographic data, indication, distance reached, macroscopic findings, microscopic findings, diagnosis, additional procedures, and complications.

RESULTS

There were a total of 999 colonoscopies. The colonoscopy was normal in 390 of 999 (39%). The commonest indication for colonoscopy was a diagnosis of suspected IBD, 449 of 999 (45%). IBD was confirmed in 282 of 449 (63%), but colonoscopy was normal in 143 of 449 (32%) of suspected IBD. Colonoscopy was performed for rectal bleeding in 197 of 999 (20%) of whom 141 of 197 (72%) were normal. There were 46 (5%) colonoscopies performed for recurrent abdominal pain, which were all normal. Our completion rate to the cecum and beyond was 521 of 999 (52%). Our perforation rate during the 10 years was 0.2%.

CONCLUSIONS

Colonoscopy is a safe procedure in pediatrics; however, 39% of colonoscopies in this series were normal. Many of these could have been avoided by eliminating colonoscopy in patients with recurrent abdominal pain in the absence of other clinical features, conservative management with laxatives for those with fresh blood per rectum typical of anal fissures, and fecal calprotectin screening before endoscopy in patients with suspected IBD.

Clinicopathologic and Molecular Features of Colorectal Adenocarcinoma with Signet-Ring Cell Component

Background

We performed a retrospective study to assess the clinicopathological characters, molecular alterations and multigene mutation profiles in colorectal cancer patients with signet-ring cell component.

Methods

Between November 2008 and January 2015, 61 consecutive primary colorectal carcinomas with signet-ring cell component were available for pathological confirmation. RAS/BRAF status was performed by direct sequencing. 14 genes associated with hereditary cancer syndromes were analyzed by targeted gene sequencing.

Results

A slight male predominance was detected in these patients (59.0%). Colorectal carcinomas with signet-ring cell component were well distributed along the large intestine. A frequently higher TNM stage at the time of diagnosis was observed, compared with the conventional adenocarcinoma. Family history of malignant tumor was remarkable with 49.2% in 61 cases. The median OS time of stage IV patients in our study was 14 months. RAS mutations were detected in 22.2% (12/54) cases with KRAS mutations in 16.7% (9/54) cases and Nras mutations in 5.4%(3/54) cases. BRAF V600E mutation was detected in 3.7% (2/54) cases. As an exploration, we analyzed 14 genes by targeted gene sequencing. These genes were selected based on their biological role in association with hereditary cancer syndromes. 79.6% cases carried at least one pathogenic mutation. Finally, the patients were classified by the percentage of signet-ring cell. 39 (63.9%) cases were composed of ≥50% signet-ring cells; 22 (36.1%) cases were composed of <50% signet-ring cells. We compared clinical parameters, molecular and genetic alterations between the two groups and found no significant differences.

Conclusions

Colorectal adenocarcinoma with signet-ring cell component is characterized by advanced stage at diagnosis with remarkable family history of malignant tumor. It is likely a negative prognostic factor and tends to affect male patients with low rates of RAS /BRAF mutation. Colorectal patients with any component of signet-ring cells, regardless of the extent, shared similar clinicopathological characteristics, molecular alterations and genetic profiles.

Tumor and Patient Characteristics of Individuals with Mismatch Repair Deficient Colorectal Cancer

AIMS

To investigate tumor and patient characteristics of individuals with mismatch repair (MMR)-deficient colorectal carcinomas.

METHODS

We immunhistochemically investigated tissue samples of 307 consecutive patients with colorectal cancer for defects in DNA MMR proteins (hMLH1, hMSH2, hMSH6, hPMS2) and those with mutations further for microsatellite instability (MSI) and BRAF V600E mutations.

RESULTS

32/308 (10.4%) tumors showed MMR deficiency. Seventy five percent (n = 24) had loss of hMLH1 and hPMS2 expression, 3% (n = 1) of hPMS2 alone, 18.8% (n = 6) of hMSH6 and hMSH2, 3% (n = 1) of hMSH2 alone. All MMR-deficient tumors showed high MSI. These tumors occurred preferably in the right-sided colon, in women and showed specific histological features. We obtained the family history of 18/32 patients; 2 (11.1%) met Amsterdam Criteria, 5 (27.8%) Bethesda Guidelines and 6 (33.3%) revised Bethesda Guidelines. BRAF V600E mutations were found in 16 (67%) of hMLH1 and none of the hMSH2 deficient tumors.

CONCLUSION

We suggest using immunhistochemical testing of tumor tissues with subsequent MSI analysis, which may be justified as a screening method for MMR deficiency in colorectal cancer, since it identifies patients with possibly hereditary defects and unalike response to chemotherapy.

Genetic architecture of colorectal cancer

Colorectal cancer (CRC) is a complex disease that develops as a consequence of both genetic and environmental risk factors. A small proportion (3-5%) of cases arise from hereditary syndromes predisposing to early onset CRC as a result of mutations in over a dozen well defined genes. In contrast, CRC is predominantly a late onset 'sporadic' disease, developing in individuals with no obvious hereditary syndrome. In recent years, genome wide association studies have discovered that over 40 genetic regions are associated with weak effects on sporadic CRC, and it has been estimated that increasingly large genome wide scans will identify many additional novel genetic regions. Subsequent experimental validations have identified the causally related variant(s) in a limited number of these genetic regions. Further biological insight could be obtained through ethnically diverse study populations, larger genetic sequencing studies and development of higher throughput functional experiments. Along with inherited variation, integration of the tumour genome may shed light on the carcinogenic processes in CRC. In addition to summarising the genetic architecture of CRC, this review discusses genetic factors that modify environmental predictors of CRC, as well as examples of how genetic insight has improved clinical surveillance, prevention and treatment strategies. In summary, substantial progress has been made in uncovering the genetic architecture of CRC, and continued research efforts are expected to identify additional genetic risk factors that further our biological understanding of this disease. Subsequently these new insights will lead to improved treatment and prevention of colorectal cancer.

Novel APC promoter and exon 1B deletion and allelic silencing in three mutation-negative classic familial adenomatous polyposis families

Background

The overwhelming majority (approximately 80%) of individuals with classic familial adenomatous polyposis (FAP) exhibit mutations in the coding sequence of the adenomatous polyposis coli (APC) tumor suppressor gene. Families without detectable APC mutations are unable to benefit from the use of genetic testing for clinical management of this autosomal dominant syndrome.

Methods

We used exome sequencing and linkage analysis, coupled with second-generation sequencing of the APC locus including non-coding regions to investigate three APC mutation-negative classical FAP families.

Results

We identified a novel ~11 kb deletion localized 44 kb upstream of the transcription start site of APC that encompasses the APC 1B promoter and exon. This deletion was present only in affected family members of one kindred with classical FAP. Furthermore, this same deletion with identical breakpoints was found in the probands of two additional APC mutation-negative classical FAP kindreds. Phasing analysis of single nucleotide polymorphisms (SNPs) around the deletion site in the three probands showed evidence of a shared haplotype, suggesting a common founder deletion in the three kindreds. SNP analysis within the coding sequence of APC, revealed that this ~11 kb deletion was accompanied by silencing of one of the APC alleles in blood-derived RNA of affected individuals.

Conclusions

These results support the causal role of a novel promoter deletion in FAP and suggest that non-coding deletions, identifiable using second-generation sequencing methods, may account for a significant fraction of APC mutation-negative classical FAP families.

The effect of disease risk probability and disease type on interest in clinic-based versus direct-to-consumer genetic testing services

The effect of disease-specific cognitions on interest in clinic-based and direct-to-consumer (DTC) genetic testing was assessed. Participants (N = 309) responded to an online hypothetical scenario and received genetic testing-related messages that varied by risk probability (25, 50, 75 %) and disease type (Alzheimer's disease vs. Type 2 Diabetes). Post-manipulation interest increased for both testing types, but was greater for clinic-based testing. Interest was greater for Type 2 Diabetes than for Alzheimer's disease, the latter perceived as more severe and likely, and less treatable and preventable. For DTC testing only, participants allocated to the high risk condition (75 %) had greater testing interest than those in the low (25 %) category. DTC testing is perceived as a viable, but less preferred, option compared with clinic-based testing. Particularly when considering DTC genetic testing, there is a need to emphasize subjective disease-related perceptions, including risk probability.

ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes

This guideline presents recommendations for the management of patients with hereditary gastrointestinal cancer syndromes. The initial assessment is the collection of a family history of cancers and premalignant gastrointestinal conditions and should provide enough information to develop a preliminary determination of the risk of a familial predisposition to cancer. Age at diagnosis and lineage (maternal and/or paternal) should be documented for all diagnoses, especially in first- and second-degree relatives. When indicated, genetic testing for a germline mutation should be done on the most informative candidate(s) identified through the family history evaluation and/or tumor analysis to confirm a diagnosis and allow for predictive testing of at-risk relatives. Genetic testing should be conducted in the context of pre- and post-test genetic counseling to ensure the patient's informed decision making. Patients who meet clinical criteria for a syndrome as well as those with identified pathogenic germline mutations should receive appropriate surveillance measures in order to minimize their overall risk of developing syndrome-specific cancers. This guideline specifically discusses genetic testing and management of Lynch syndrome, familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, serrated (hyperplastic) polyposis syndrome, hereditary pancreatic cancer, and hereditary gastric cancer.

Ulcerative colitis with inflammatory polyposis in a teenage boy: A case report

Ulcerative colitis in addition to inflammatory polyposis is common. The benign sequel of ulcerative colitis can sometimes mimic colorectal carcinoma. This report describes a rare case of inflammatory polyposis with hundreds of inflammatory polyps in ulcerative colitis which was not easy to distinguish from other polyposis syndromes. A 16-year-old Chinese male suffering from ulcerative colitis for 6 mo underwent colonoscopy, and hundreds of polyps were observed in the sigmoid, causing colonic stenosis. The polyps were restricted to the sigmoid. Although rectal inflammation was detected, no polyps were found in the rectum. A diagnosis of inflammatory polyposis and ulcerative colitis was made. The patient underwent total colectomy and ileal pouch anal anastomosis. The patient recovered well and was discharged on postoperative day 8. Endoscopic surveillance after surgery is crucial as ulcerative colitis with polyposis is a risk factor for colorectal cancer. Recognition of polyposis requires clinical, endoscopic and histopathologic correlation, and helps with chemoprophylaxis of colorectal cancer, as the drugs used postoperatively for colorectal cancer, ulcerative colitis and polyposis are different.

Role of MYH polymorphisms in sporadic colorectal cancer in China: a case-control, population-based study

PURPOSE

Biallelic germline variants of the 8-hydroxyguanine (8-OG) repair gene MYH have been associated with colorectal neoplasms that display somatic G:C?T:A transversions. However, the effect of single germline variants has not been widely studied, prompting the present investigation of monoallelic MYH variants and susceptibility to sporadic colorectal cancer (CRC) in a Chinese population.

PATIENTS AND METHODS

Between January 2006 and December 2012, 400 cases of sporadic CRC and 600 age- and sex-matched normal blood donors were screened randomly for 7 potentially pathogenic germline MYH exons using genetic testing technology. Variants of heterozygosity at the MYH locus were assessed in both sporadic cancer patients and healthy controls. Univariate and multivariate analyses were performed to determine risk factors for cancer onset.

RESULTS

Five monoallelic single nucleotide polymorphisms (SNPs) were identified in the 7 exon regions of MYH, which were detected in 75 (18.75%) of 400 CRC patients as well as 42 (7%) of 600 normal controls. The region of exon 1 proved to be a linked polymorphic region for the first time, a triple linked variant including exon 1-316 G?A, exon 1-292 G?A and intron 1+11 C?T, being identified in 13 CRC patients and 2 normal blood donors. A variant of base replacement, intron 10-2 A?G, was identified in the exon 10 region in 21 cases and 7 controls, while a similar type of variant in the exon 13 region, intron 13+12 C?T, was identified in 8 cases and 6 controls. Not the only but a newly missense variant in the present study, p. V463E (Exon 14+74 T?A), was identified in exon 14 in 6 patients and 1 normal control. In exon 16, nt. 1678-80 del GTT with loss of heterozygosity (LOH) was identified in 27 CRC cases and 26 controls. There was no Y165C in exon 7 or G382D in exon 14, the hot- spot variants which have been reported most frequently in Caucasian studies. After univariate analysis and multivariate analysis, the linked variant in exon 1 region (p=0.002), intron 10-2 A?G (p=0.004) and p. V463E (p=0.036) in the MYH gene were selected as 3 independent risk factors for CRC.

CONCLUSIONS

According to these results, the linked variant in Exon 1 region, Intron 10-2 A?G of base replacement and p. V463E of missense variant, the 3 heterozygosity variants of MYH gene in a Chinese population, may relate to the susceptibility to sporadic CRC. Lack of the hot-spot variants of Caucasians in the present study may due to the ethnic difference in MYH gene.

Diagnostic accuracy of fecal immunochemical test in average- and familial-risk colorectal cancer screening

BACKGROUND

There is little information about the fecal immunochemical test (FIT) in familial-risk colorectal cancer (CRC) screening.

OBJECTIVES

The objective of this article is to investigate whether FIT diagnostic accuracy for advanced neoplasia (AN) differs between average and familial-risk (first-degree relative) patients.

METHODS

A total of 1317 consecutive participants (595 familial) who collected one stool sample before performing a colonoscopy as a CRC screening test were included. FIT diagnostic accuracy for AN was evaluated with Chi-square test at a 20 µg hemoglobin/g of feces cut-off value. Finally, we determined which variables were independently related to AN.

RESULTS

An AN was found in 151 (11.5%) patients. The overall accuracy was not statistically different between both cohorts for AN (88.4%, 91.7%; p = 0.051). At the cut-off stablished, differences in FIT sensitivity (31.1%, 40.6%; p = 0.2) or specificity (96.5%, 97.3%; p = 0.1) were not statistically significant. Finally, independent variables such as sex (male) (odds ratio (OR) 2.1, 95% confidence interval (CI) 1.4-3.1), age (50-65, >65 years) (OR 2.1, 95% CI 1.1-4.3; OR 2.7, 95% CI 1.2-6.1), previous colonoscopy (OR 0.4, 95% CI 0.2-0.9) and FIT ≥20 µg/g feces (OR 17.7, 95% CI 10.8-29.1) were associated with AN diagnosis.

CONCLUSIONS

FIT accuracy for AN detection is equivalent in average and familial-risk CRC screening cohorts.

Analysis of current testing practices for biallelic MUTYH mutations in MUTYH-associated polyposis

MUTYH-associated polyposis (MAP) is an autosomal recessive syndrome caused by biallelic mutations in the base excision repair gene MUTYH. Owing to potential limitations in the MAP testing strategy and testing criteria, it is possible that MAP is being under-identified both genotypically and phenotypically. To determine whether full sequencing of MUTYH would increase clinical sensitivity over a founder mutation (FM) strategy, a retrospective analysis of two datasets from a commercial clinical laboratory was performed. The first cohort contained 1522 individuals who received MUTYH analysis for two FMs with subsequent full-gene sequencing. Eighty-five biallelic individuals were identified; 47 carried two FMs, 17 carried one FM and one mutation identified on full sequencing, and 21 carried biallelic mutations identified only on full sequencing. The second cohort contained 921 patients with colorectal cancer <50 years and <10 reported colorectal adenomas who had undergone MUTYH mutation testing. In this cohort, 19 of 921 (2.1%) individuals were identified as biallelic MUTYH carriers. Of these, 13 did not have a personal or family history of polyps and would not have met guidelines for MUTYH testing. These results suggest that individuals with biallelic MUTYH mutations are under-ascertained based on both genotype and phenotype under current standard testing practices.

Consensus on the Prevention, Screening, Early Diagnosis and Treatment of Colorectal Tumors in China: Chinese Society of Gastroenterology, October 14-15, 2011, Shanghai, China

BACKGROUND

Colorectal cancer (CRC) is steadily increasing in China. Colorectal adenoma (CRA) is the most important precancerous disease of CRC. Screening for colorectal tumors can aid early diagnosis. Advances in endoscopic mucosal resection and endoscopic submucosal dissection can aid the early treatment of colorectal tumors. Furthermore, because of high risk of recurrence after removal of adenomas under endoscopy, factors contributing to recurrence, the follow-up mode and the interval established, and the feasibility of application and the time of various chemical preventions should be concerned. However, a relevant consensus on the screening, early diagnosis and treatment, and prevention of colorectal tumors in China is lacking.

SUMMARY

The consensus recommendations include epidemiology, pathology, screening, early diagnosis, endoscopic treatment, monitoring and follow-up, and chemoprevention of colorectal tumors in China.

KEY MESSAGE

This is the first consensus on the prevention, screening, early diagnosis and treatment of CRA and CRC in China based on evidence in the literature and on local data.

PRACTICAL IMPLICATIONS

Through reviewing the literature, regional data and passing the consensus by an anonymous vote, gastroenterology experts from all over China launch the consensus recommendations in Shanghai. The incidence and mortality of CRC in China has increased, and the incidence or detection rate of CRA has increased rapidly. Screening for colorectal tumors should be performed at age 50-74 years. Preliminary screening should be undertaken to find persons at high risk, followed by colonoscopy. A screening cycle of 3 years is recommended for persistent interventions. Opportunistic screening is a mode suitable for the current healthcare system and national situation. Colonoscopy combined with pathological examination is the standard method for the diagnosis of colorectal tumors. CRA removal under endoscopy can prevent CRC to some extent, but CRA has an obvious recurrence trend. The follow-up interval after the removal or surgery of colorectal tumors should be different with lesions. Primary prevention of CRA includes improved diet with more fiber, supplements containing calcium and vitamin D, supplements containing folic acid for those with low hemoglobin levels, and cessation of tobacco smoking. Non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors have been recognized to prevent recurrence after adenoma removal.

PTEN germline mutations in patients initially tested for other hereditary cancer syndromes: would use of risk assessment tools reduce genetic testing?

PURPOSE

PTEN Hamartoma Tumor syndrome (PHTS) includes patients with Cowden syndrome or other syndromes with germline mutation of the PTEN tumor suppressor gene. The risk for breast, colorectal, and endometrial cancer and polyposis is increased, creating clinical overlap with hereditary breast and ovarian cancer (HBOC), Lynch syndrome (LS), and adenomatous polyposis syndromes (APS). We reviewed our series of patients with PHTS to determine how often testing criteria for these syndromes were met and how often other-gene testing was ordered before testing PTEN.

PATIENTS AND METHODS

Patients were prospectively recruited by relaxed International Cowden Consortium criteria or presence of known germline PTEN mutation. Mutations were identified by mutation scanning/multiplex ligation-dependent probe amplification analysis and confirmed by sequencing/quantitative polymerase chain reaction. Patients were excluded if they were adopted, were <18 years of age, or if they were diagnosed with Cowden syndrome before 1998. Standard risk-assessment models were applied to determine whether patients met HBOC testing criteria, LS-relevant Amsterdam II/Bethesda 2004 criteria, or had adenomatous polyps. Prior probability of PTEN mutation was estimated with the Cleveland Clinic PTEN risk calculator.

RESULTS

Of 137 PTEN mutation-positive adult probands, 59 (43.1%) met testing criteria for HBOC or LS. Of these, 45 (32.8%) were first offered HBOC, LS, or APS testing. Of those who underwent APS testing, none of the six patients met criteria. Initial risk assessment by a genetics specialist was significantly associated with immediate PTEN testing in patients also meeting HBOC testing criteria. Using this PTEN risk assessment tool could have spared gene testing for 22 unlikely syndromes, at a total cost of $66,080.

CONCLUSION

PHTS is an important differential diagnosis for patients referred for HBOC, LS, or APS. Risk assessment tools may help focus genetic analysis and aid in the interpretation of multiplex testing.

Identification of patients at risk for hereditary colorectal cancer

Diagnosis of hereditary colorectal cancer syndromes requires clinical suspicion and knowledge of such syndromes. Lynch syndrome is the most common cause of hereditary colorectal cancer. Other less common causes include familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome (PJS), juvenile polyposis syndrome, and others. There have been a growing number of clinical and molecular tools used to screen and test at risk individuals. Screening tools include diagnostic clinical criteria, family history, genetic prediction models, and tumor testing. Patients who are high risk based on screening should be referred for genetic testing.

Advanced precancerous lesions (APL) in the colonic mucosa

Colorectal cancer is a leading cause of cancer death worldwide. Most colorectal cancers are preventable. Surveillance colonoscopy is used to detect and remove precancerous lesions. Although the majority of precancerous lesions develop sporadically, some have an inherited component. In this review, we summarize the clinical, pathologic, and molecular features of advanced precancerous lesions of the colon. The most common and clinically important intestinal polyposis syndromes, and their genetics, are also discussed. Finally, current recommendations regarding the treatment and surveillance of precancerous lesions, both in the sporadic and in inherited setting, are reviewed.

Inflammatory bowel disease and familial adenomatous polyposis

BACKGROUND

Inflammatory bowel disease (IBD) and familial adenomatous polyposis (FAP) are uncommon diseases and both are associated with marked increased risk of colorectal cancer.

METHODS

We present a patient diagnosed in parallel with ulcerative colitis and FAP. Mutational analysis of the APC germline and somatic DNA was performed by sequencing.

RESULTS

This patient's phenotype consisted of polyps only on the right side of the colon (cecum and ascending colon) whereas the area affected by ulcerative colitis (descending colon and rectum) was free of polyps on endoscopy and microscopic adenomas on histology. This raises the possibility that mosaicism or inflammation in the presence of active ulcerative colitis modified the phenotypic expression of adenomatous polyposis in the left colon. Mosaicism was excluded by DNA analysis.

DISCUSSION

This case of a patient diagnosed with both inflammatory bowel disease and familial adenomatous polyposis offers potential insights into the distinct pathogenesis of cancer susceptibility within these syndromes, and suggests that a collision of phenotypes may influence their mutual presentation. Both of these conditions independently increase the risk of colorectal cancer.

Increasing Lynch syndrome identification through establishment of a hereditary colorectal cancer registry

BACKGROUND

Lynch syndrome contributes to 5% of all colorectal cancers. Patients seen in most surgical clinics have limited or no family histories documented and are rarely assessed for hereditary syndromes. In 2007 a clinic-based hereditary colorectal cancer registry was established to screen for Lynch syndrome and facilitate genetic counseling/testing.

OBJECTIVE

To evaluate the effectiveness of the hereditary colorectal cancer registry to identify high-risk colorectal cancer patients and have them referred for genetic counseling/testing for Lynch syndrome.

DESIGN

A retrospective review and cohort comparison of both prospectively collected and retrospective data.

SETTING

The colorectal surgical clinic at Vanderbilt University Medical Center.

PATIENTS

All newly diagnosed colorectal cancer patients seen between January 2006 and October 2010.

MAIN OUTCOME MEASURES

To assess the identification of colorectal cancer patients at high risk for Lynch syndrome and for the occurrence of genetic counseling/testing before and after the establishment of a hereditary registry by comparing the results from the colorectal cancer patients seen the year prior to the establishment of the registry (January - December 2006, "control period") with those patients seen after initiation of the registry (January 2007 - October 2010, "registry period").

RESULTS

During the "registry period," 495 colorectal cancer patients were seen in the clinic and 257 (51.9%) were high risk for Lynch syndrome. Forty-nine patients (9.8%) underwent genetic testing, with 27 (5.4%) positive for a gene mutation, of which half were >50 years old. By comparison, in 2006, 115 colorectal cancer patients were seen in the clinic but only 4 patients (3.5%) went on for further assessment, and only 1 had genetic testing. Retrospective assessment showed that at least 22 patients (19.1%) had warranted further investigation in 2006.

LIMITATIONS

This was a single-institution, retrospective review.

CONCLUSION

Establishment of a hereditary colorectal cancer registry with a clinic-based protocol improves identification of Lynch syndrome.

Key genetic considerations in the management of suspected hereditary colorectal cancer

SUMMARY Hereditary bowel cancer syndromes account for up to 5% of colorectal cancer (CRC) incidence. Presentation of CRC under the age of 50 years should alert clinicians to a possible underlying genetic predisposition. This article focuses on Lynch syndrome (hereditary nonpolyposis CRC). Regular bowel screening is effective in reducing the risk of CRC and improving overall survival in Lynch syndrome families. The issues surrounding the clinical diagnostic criteria and the shortcomings of the referral process are described, and it is questioned whether a universal strategy for diagnosis should be employed. This article summarizes the evidence for the benefit of bowel screening and suggests practical steps to help ensure compliance with screening recommendations. Finally, it is discussed how collaboration between geneticists, gastroenterologists and surgeons can inform surgical decision-making for the benefit of the patient.

A De Novo Germline APC Mutation (3927del5) in a Patient with Familial Adenomatous Polyposis: Case Report and Literature Review

Introduction

Characterized by the development of hundreds to thousands of colonic adenomas, classic familial adenomatous polyposis (FAP) is one of the most common hereditary syndromes associated with an increased risk of colorectal cancer. Several studies have attempted to correlate specific APC mutations with clinical phenotype.6 However, there is considerable variability in the expression of specific phenotypes within families and among individuals with identical mutations.7

Case presentation

A 30 year-old Hispanic female presented to the emergency department with a 2-week history of persistent, worsening, left lower quadrant abdominal pain. She had no family history of malignancy. Sigmoidoscopy revealed innumerable polyps in the rectum and sigmoid colon and a large mass in the sigmoid colon. Biopsy of the mass revealed a moderately differentiated adenocarcinoma invading the subserosa. Endoscopy revealed innumerable polyps. Genetic testing of the patient via southern blot revealed a germline APC mutation 3927del5, resulting in a premature truncation of the APC protein at amino acid position 1312.

Conclusion

Genetic information has only recently started being incorporated into clinical care. More research and randomized clinical trials need to be conducted to definitively characterize random mutations. Once these mutations are further understood, FAP patients may be able to be risk stratified and this may ultimately improve the screening, diagnosis, and treatment of this rare condition.

Translational advances regarding hereditary breast cancer syndromes

Approximately 5-10% of breast cancers may be inheritable, up to 90% of which are due to mutations in BRCA1 and BRCA2. A substantial minority are caused by non-BRCA mutations, such as TP53, PTEN, STK11, CHEK2, ATM, BRIP1, and PALB2 mutations. This review highlights translational research advances with regard to the development of probabilistic models for hereditary breast cancer syndromes, the identification of specific genetic mutations responsible for these syndromes, as well as their testing and interpretations.

Screening for Familial Colorectal Cancer Risk amongst Colonoscopy Patients New to an Open-Access Endoscopy Center

Purpose. We evaluated a questionnaire to aid in the recognition of CRC risk, as well as patient interest in their risk status within an open-access endoscopy center. Methods. A questionnaire was administered to new patients presenting for colonoscopy from May 2007 to February 2008. 287 patients were enrolled. Family history was evaluated using Amsterdam 1, II, and Revised Bethesda criteria. Recognition of risk and referral for counseling was assessed. Patients' interest to be contacted by a genetic counselor was also assessed. Results. 13.2 % (38/287) of patients met Revised Bethesda criteria. Of these, 18 (47.4 %) were previously told about their increased risk for CRC. Only 1 patient who met Revised Bethesda criteria (2.6 %) was previously referred for genetics, whereas none of the 3 patients who met Amsterdam I or II criteria were referred. 23.7 % of high-risk patients did not want to be contacted if found to be at increased risk for cancer. Conclusion. In our open-access endoscopy system, a significant number of high-risk patients remain unidentified and underreferred for genetic counseling due to numerous barriers. Our findings lend support to taking a public health approach to identifying those at risk for Lynch syndrome by implementing universal screening of all CRC specimens.

Incidence of subsequent pancreatic adenocarcinoma in patients with a history of nonpancreatic primary cancers

BACKGROUND

Several environmental risk factors are known to predispose individuals to pancreatic cancer, and up to 15% of pancreatic cancers have an inherited component. Understanding metachronous cancer associations can modify pancreas cancer risk. The objective of this study was to investigate the association of nonpancreatic cancers with subsequent pancreatic adenocarcinoma.

METHODS

The authors used data from the US Surveillance, Epidemiology, and End Results (SEER) registries to identify 1,618,834 individuals who had a primary malignancy and subsequent pancreatic adenocarcinoma (n = 4013). Standardized incidence ratios were calculated as an approximation of relative risk (RR) for the occurrence of pancreatic adenocarcinoma after another primary malignancy.

RESULTS

Among patients who were diagnosed with a first primary malignancy at ages 20 to 49 years, the risk of subsequent pancreatic adenocarcinoma was increased among patients who had cancers of the ascending colon (relative risk [RR], 4.62; 95% confidence interval [CI], 1.86-9.52), hepatic flexure (RR, 5.42; 95% CI, 1.12-15.84), biliary system (RR, 13.14; 95% CI, 4.27-30.66), breast (RR, 1.32; 95% CI, 1.09-1.59), uterine cervix (RR, 1.61; 95% CI, 1.02-2.41), testes (RR, 2.78; 95% CI, 1.83-4.05), and hematopoietic system (RR, 1.83; 95% CI, 1.28-2.53). Among patients who had a first malignancy at ages 50 to 64 years, the risk was increased after cancers of the stomach (RR, 1.88; 95% CI, 1.13-2.93), hepatic flexure (RR, 2.25; 95% CI, 1.08-4.13), lung and bronchus (RR, 1.46; 95% CI, 1.16-1.82), pharynx (RR, 2.26; 95% CI, 1.13-4.04), and bladder (RR, 1.24; 95% CI, 1.03-1.48). Among patients who had a primary cancer after age 65 years, the risk was increased after cancers of the stomach (RR, 1.79; 95% CI, 1.23-2.53), hepatic flexure (RR, 1.76; 95% CI, 1.06-2.75), biliary system (RR, 2.35; 95% CI, 1.17-4.20), and uterus (RR, 1.23; 95% CI, 1.03-1.47).

CONCLUSIONS

The results from the current population-based data set suggested that pancreatic adenocarcinoma is associated with certain primary cancers. Genetic predisposition and common environmental and behavioral risk factors all may contribute to this observation. Specific tumor associations will guide future risk-stratification efforts.

Colorectal polyps: a frequently-missed cause of rectal bleeding in Egyptian children

OBJECTIVES

Colorectal polyps are important causes of rectal bleeding but they have been infrequently reported in Egyptian children. The prevalence and characteristics of colorectal polyps in a consecutive cohort of Egyptian children with rectal bleeding are presented.

METHODS

A total of 174 children aged 2-12 years [mean (SD) 6.4 (3.7)] with fresh rectal bleeding were enrolled prospectively. Rectal examination, laboratory investigations and fibre-optic colonoscopy were performed in all patients.

RESULTS

The source of bleeding was diagnosed as colorectal polyps in 100 patients (57.4%) and was owing to other causes in 74. The interval between onset of symptoms and presentation ranged from 2 to 48 months [mean (SD) 18.3 (16)]. In patients with other causes, rectal bleeding was attributed to intestinal amoebiasis (42), diarrhoea/dysentery (18), severe constipation (2) and intestinal schistosomiasis (2). Polyps were solitary in 56 children (56%) and ranged from 2 to 5 in 34 (34%) and >5 in 10 (10%). Polyps were confined to the rectum in 68 children, were rectosigmoid in 20, in the descending colon in 8, and splenic flexure in 4. Polyps were juvenile in 84 children (84%), inflammatory in 10 (10%) and hyperplastic, schistosomal or adenomatous in 2 each (6%). Colonoscopic polypectomy was successful and arrested the bleeding in all cases.

CONCLUSION

In Egyptian children, colorectal polyps are relatively common and an easily treatable cause of fresh rectal bleeding. They should be high on the list of differential diagnoses.

Hereditary colon cancer syndromes

Colon cancer is associated with a family history in up to 25% of cases. As many as 5% are associated with an established hereditary syndrome, demonstrating the profound influence of inheritable genetic mechanisms in the development of this disease. These syndromes confer a diverse spectrum of risk, age of presentation, endoscopic and histological findings, extracolonic manifestations, and modes of inheritance. As the molecular characteristics of these disorders become better described, enhanced genotype-phenotype correlations may offer a more targeted approach to diagnosis, screening, and surveillance. While the strategies for diagnosis and management of familial adenomatous polyposis (FAP) and Lynch syndrome are more established, the approach to newly recognized syndromes such as MUTYH-associated polyposis (MAP) and hyperplastic polyposis syndromes continues to evolve. Effective cancer prevention in affected individuals and at-risk family members first requires timely recognition of these hereditary colon cancer syndromes followed by integration of genetic testing and clinical examinations.

Informed consent to microsatellite instability and immunohistochemistry screening for Lynch syndrome

OBJECTIVE

Routine microsatellite instability and immunohistochemistry screening of colorectal cancers can assist in identifying a significant proportion of cancers attributable to Lynch syndrome. This article considers whether it is necessary to obtain patient informed consent for microsatellite instability and immunohistochemistry screening.

RESULTS

Although microsatellite instability screening examines genetic features of a tumor, it lacks several important characteristics that typically mandate formal informed consent to genetic testing. Microsatellite instability screening describes discrete tissue samples and does not provide information about the rest of the patient's body or germline. In contrast, immunohistochemistry screening is a proteomic test that may reveal information about the patient's germline. As such, immunohistochemistry screening can be viewed as similar to other forms of genetic testing, in which explicit patient consent is regarded as an ethical prerequisite.

CONCLUSION

There is no ethical requirement to obtain explicit informed consent for microsatellite instability screening of colorectal tumor samples for Lynch syndrome. There is support for obtaining patient consent to immunohistochemistry testing, given its similarities with other genetic analyses for which informed consent is typically deemed necessary. Regardless of which screening test is used, it is important to prepare patients and their families for the possibility of a positive screening test.

Inherited colorectal cancer syndromes

Colorectal cancer is common in the Western world; ~5% of individuals diagnosed with colorectal cancer have an identifiable inherited genetic predisposition to this malignancy. Genetic testing and rational clinical management recommendations currently exist for the management of individuals with a variety of colorectal cancer syndromes, including hereditary nonpolyposis colorectal cancer (HNPCC, also known as Lynch syndrome), familial adenomatous polyposis (FAP), MYH-associated polyposis (MAP), and the hamartomatous polyposis syndromes (Peutz-Jeghers, juvenile polyposis, and Cowden disease). In addition to colorectal neoplasia, these syndromes frequently predispose carriers to a variety of extracolonic cancers. The elucidation of the genetic basis of several colorectal cancer predisposition syndromes over the past two decades has allowed for better management of individuals who are either affected with, or at-risk for inherited colorectal cancer syndromes. Appropriate multidisciplinary management of these individuals includes genetic counseling, genetic testing, clinical screening, and treatment recommendations.