Diagnostic criteria for constitutional mismatch repair deficiency (CMMRD): recommendations from the international consensus working group.

BACKGROUND: Constitutional mismatch repair deficiency syndrome (CMMRD) is the most aggressive cancer predisposition syndrome associated with multiorgan cancers, often presenting in childhood. There is variability in age and presentation of cancers and benign manifestations mimicking neurofibromatosis type 1. Genetic testing may not be informative and is complicated by pseudogenes associated with the most commonly associated gene, PMS2. To date, no diagnostic criteria exist. Since surveillance and immune-based therapies are available, establishing a CMMRD diagnosis is key to improve survival. METHODS: In order to establish a robust diagnostic path, a multidisciplinary international working group, with representation from the two largest consortia (International Replication Repair Deficiency (IRRD) consortium and European Consortium Care for CMMRD (C4CMMRD)), was formed to establish diagnostic criteria based on expertise, literature review and consensus. RESULTS: The working group established seven diagnostic criteria for the diagnosis of CMMRD, including four definitive criteria (strong evidence) and three likely diagnostic criteria (moderate evidence). All criteria warrant CMMRD surveillance. The criteria incorporate germline mismatch repair results, ancillary tests and clinical manifestation to determine a diagnosis. Hallmark cancers for CMMRD were defined by the working group after extensive literature review and consultation with the IRRD and C4CMMRD consortia. CONCLUSIONS: This position paper summarises the evidence and rationale to provide specific guidelines for CMMRD diagnosis, which necessitates appropriate surveillance and treatment.

Risk assessment and genetic counseling for Lynch syndrome - Practice resource of the National Society of Genetic Counselors and the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer.

Identifying individuals who have Lynch syndrome involves a complex diagnostic workup that includes taking a detailed family history and a combination of various tests such as immunohistochemistry and/or molecular which may be germline and/or somatic. The National Society of Genetic Counselors and the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer have come together to publish this practice resource for the evaluation of Lynch syndrome. The purpose of this practice resource was to provide guidance and a testing algorithm for Lynch syndrome as well as recommendations on when to offer testing. This practice resource does not replace a consultation with a genetics professional. This practice resource includes explanations in support of this and a summary of background data. While this practice resource is not intended to serve as a review of Lynch syndrome, it includes a discussion of background information and cites a number of key publications which should be reviewed for a more in-depth understanding. This practice resource is intended for genetic counselors, geneticists, gastroenterologists, surgeons, medical oncologists, obstetricians and gynecologists, nurses, and other healthcare providers who evaluate patients for Lynch syndrome.

Prevalence of Germline Mutations in Polyposis and Colorectal Cancer-Associated Genes in Patients With Multiple Colorectal Polyps.

BACKGROUND AND AIMS: Guidelines recommend genetic testing of patients with 10 or more cumulative adenomatous polyps. However, little is known about the utility of these tests-especially for older patients. We aimed to determine the prevalence of pathogenic mutations in patients with multiple colorectal polyps, stratified by age. METHODS: We performed a cross-sectional study of patients with 10 or more colorectal polyps who underwent multigene panel testing (MGPT) from March 2012 through December 2016 (n = 3789). Demographic, clinical and family history data were obtained from test requisition forms and accompanying clinic notes, pedigrees, and pathology reports. Subjects were stratified based on reported polyp histology. Primary outcomes of interest were gene mutations associated with adenomatous polyposis, hamartomatous polyposis, and non-polyposis colorectal cancer syndromes. RESULTS: Based on MGPT, the prevalence of mutations in adenomatous polyposis genes decreased with increasing age in all polyp count groups in the adenoma cohort (P < .001 for 10-19, 20-99, and 100 or more polyps). The prevalence of mutations in all genes of interest also decreased with increasing age but remained above 5% in all age and polyp cohorts. Increased age at testing was associated with a significantly lower risk of a mutation in any gene of interest with multivariate analysis. In the hamartoma cohort, the prevalence of mutations in hamartomatous polyposis genes was high regardless of polyp count (40% with 10-19 polyps, 72.1% with 20-99 polyps, and 50% with 100 or more polyps). CONCLUSION: Our findings support continued genetic testing of patients with 10 or more polyps including adenomas and/or hamartomas. MGPT that includes analysis of polyposis and non-polyposis colorectal cancer genes should be considered for these patients given the high proportion with mutations (above 5%) in all age groups.

An alternative approach to establishing unbiased colorectal cancer risk estimation in Lynch syndrome.

PURPOSE: Biallelic pathogenic variants in the mismatch repair (MMR) genes cause a recessive childhood cancer predisposition syndrome known as constitutional mismatch repair deficiency (CMMRD). Family members with a heterozygous MMR variant have Lynch syndrome. We aimed at estimating cancer risk in these heterozygous carriers as a novel approach to avoid complicated statistical methods to correct for ascertainment bias. METHODS: Cumulative colorectal cancer incidence was estimated in a cohort of PMS2- and MSH6-associated families, ascertained by the CMMRD phenotype of the index, by using mutation probabilities based on kinship coefficients as analytical weights in a proportional hazard regression on the cause-specific hazards. Confidence intervals (CIs) were obtained by bootstrapping at the family level. RESULTS: The estimated cumulative colorectal cancer risk at age 70 years for heterozygous PMS2 variant carriers was 8.7% (95% CI 4.3-12.7%) for both sexes combined, and 9.9% (95% CI 4.9-15.3%) for men and 5.9% (95% CI 1.6-11.1%) for women separately. For heterozygous MSH6 variant carriers these estimates are 11.8% (95% CI 4.5-22.7%) for both sexes combined, 10.0% (95% CI 1.83-24.5%) for men and 11.7% (95% CI 2.10-26.5%) for women. CONCLUSION: Our findings are consistent with previous reports that used more complex statistical methods to correct for ascertainment bias. These results underline the need for MMR gene-specific surveillance protocols for Lynch syndrome.

Somatic TP53 variants frequently confound germ-line testing results.

PURPOSE: Blood/saliva DNA is thought to represent the germ line in genetic cancer-risk assessment. Cases with pathogenic TP53 variants detected by multigene panel testing are often discordant with Li-Fraumeni syndrome, raising concern about misinterpretation of acquired aberrant clonal expansions (ACEs) with TP53 variants as germ-line results. METHODS: Pathogenic TP53 variants with abnormal next-generation sequencing metrics (e.g., decreased ratio (<25%) of mutant to wild-type allele, more than two detected alleles) were selected from a CLIA laboratory testing cohort. Alternate tissues and/or close relatives were tested to distinguish between ACE and germ-line status. Clinical data and Li-Fraumeni syndrome testing criteria were examined. RESULTS: Among 114,630 multigene panel tests and 1,454 TP53 gene-specific analyses, abnormal next-generation sequencing metrics were observed in 20% of 353 TP53-positive results, and ACE was confirmed for 91% of cases with ancillary materials, most of these due to clonal hematopoiesis. Only four met Chompret criteria. Individuals with ACE were older (50 years vs. 33.7; P = 0.02) and were identified more frequently in multigene panel tests (66/285; 23.2%) than in TP53 gene-specific tests (6/68; 8.8%, P = 0.005). CONCLUSION: ACE confounds germ-line diagnosis, may portend hematologic malignancy, and may provoke unwarranted clinical interventions. Ancillary testing to confirm germ-line status should precede Li-Fraumeni syndrome management.

Gastrointestinal Polyposis in Cowden Syndrome.

GOALS: To further characterize the gastrointestinal manifestations of Cowden syndrome in clinically well-annotated patients to improve the diagnosis of this syndrome. BACKGROUND: The gastrointestinal manifestations of Cowden Syndrome, an important heritable and multiorgan cancer syndrome, are not well defined. Proper diagnosis is essential for effective cancer surveillance and prevention in these patients. STUDY: Cowden patients with gastrointestinal polyps were selected for medical record and pathologic slide review. RESULTS: Of 19 total patients, genetic testing revealed pathogenic PTEN mutations in 12. Pan-colonic (11-patients, 58%) and pan-gastrointestinal (8-patients, 42%) polyp distributions were common. Inflammatory (juvenile) polyps were the most common of the hamartomatous polyp (18 patients, 95%), along with expansive lymphoid follicle polyps (12 patients, 63%), ganglioneuromatous polyps (10 patients, 53%), and intramucosal lipomas (5 patients, 26%). The findings of 2 or more hamartomatous polyp types per patient emerged as a newly described and highly prevalent (79%) feature of Cowden syndrome. Ganglioneuromatous polyps, rare in the general population, and intramucosal lipomas, which may be unique to Cowden syndrome, should both prompt further evaluation. Colonic adenomas and adenocarcinomas were common; 10 patients (53%) had single and 3 (16%) had ≥3 adenomas, whereas 2 (11%) had colonic adenocarcinoma, strengthening the emerging association of colorectal cancer with Cowden syndrome. CONCLUSIONS: The clinical phenotypes and gastrointestinal manifestations in Cowden syndrome are quite variable but this series adds the following new considerations for this syndromic diagnosis: multiple gastrointestinal hamartomas, especially 2 or more hamartoma types, and any intramucosal lipomas or ganglioneuromas. These features should warrant consideration of Cowden syndrome.

Effect of Sulindac and Erlotinib vs Placebo on Duodenal Neoplasia in Familial Adenomatous Polyposis: A Randomized Clinical Trial.

IMPORTANCE: Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal polyps and cancer. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful. OBJECTIVE: To evaluate the effect of a combination of sulindac and erlotinib on duodenal adenoma regression in patients with FAP. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized, placebo-controlled trial, enrolling 92 participants with FAP, conducted from July 2010 through June 2014 at Huntsman Cancer Institute in Salt Lake City, Utah. INTERVENTIONS: Participants with FAP were randomized to sulindac (150 mg) twice daily and erlotinib (75 mg) daily (n = 46) vs placebo (n = 46) for 6 months. MAIN OUTCOMES AND MEASURES: The total number and diameter of polyps in the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden at 6 months. Polyp burden was calculated as the sum of the diameters of polyps. The secondary outcomes were change in total duodenal polyp count, change in duodenal polyp burden or count stratified by genotype and initial polyp burden, and percentage of change from baseline in duodenal polyp burden. RESULTS: Ninety-two participants (mean age, 41 years [range, 24-55]; women, 56 [61%]) were randomized when the trial was stopped by the external data and safety monitoring board because the second preplanned interim analysis met the prespecified stopping rule for superiority. Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of participants receiving treatment and 20% of participants receiving placebo (P < .001). Only 2 participants experienced grade 3 adverse events. [table: see text]. CONCLUSIONS AND RELEVANCE: Among participants with FAP, the use of sulindac and erlotinib compared with placebo resulted in a lower duodenal polyp burden after 6 months. Adverse events may limit the use of these medications at the doses used in this study. Further research is necessary to evaluate these preliminary findings in a larger study population with longer follow-up to determine whether the observed effects will result in improved clinical outcomes. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT 01187901.

Colorectal Cancer Screening, Version 1.2015.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colorectal Cancer Screening provide recommendations for selecting individuals for colorectal cancer screening, and for evaluation and follow-up of colon polyps. These NCCN Guidelines Insights summarize major discussion points of the 2015 NCCN Colorectal Cancer Screening panel meeting. Major discussion topics this year were the state of evidence for CT colonography and stool DNA testing, bowel preparation procedures for colonoscopy, and guidelines for patients with a positive family history of colorectal cancer.

Esophageal and esophagogastric junction cancers, version 1.2015.

Esophageal cancer is the sixth most common cause of cancer deaths worldwide. Adenocarcinoma is more common in North America and Western European countries, originating mostly in the lower third of the esophagus, which often involves the esophagogastric junction (EGJ). Recent randomized trials have shown that the addition of preoperative chemoradiation or perioperative chemotherapy to surgery significantly improves survival in patients with resectable cancer. Targeted therapies with trastuzumab and ramucirumab have produced encouraging results in the treatment of advanced or metastatic EGJ adenocarcinomas. Multidisciplinary team management is essential for patients with esophageal and EGJ cancers. This portion of the NCCN Guidelines for Esophageal and EGJ Cancers discusses management of locally advanced adenocarcinoma of the esophagus and EGJ.

Hereditary and common familial colorectal cancer: evidence for colorectal screening.

Colorectal cancer (CRC) is the fourth most common cancer among men and women. Between 3 and 6% of all CRCs are attributed to well-defined inherited syndromes, including Lynch syndrome, familial adenomatous polyposis, MUTYH-associated polyposis and several hamartomatous conditions. Up to 30% of CRC cases exhibit common familial risk, likely related to a combination of inherited factors and environment. Identification of these patients through family history and appropriate genetic testing can provide estimates of cancer risk that inform appropriate cancer screening, surveillance and/or preventative interventions. This article examines the colon cancer syndromes, their genetic basis, clinical management and evidence supporting colorectal screening. It also deals with the category of common (non-syndromic) familial risk including risk determination and screening guidelines.

Creation of a network to promote universal screening for Lynch syndrome: the LynchSyndrome Screening Network.

The Evaluation of Genomic Applications in Practice and Prevention Working Group published an evidence-based recommendation stating that every newly diagnosed colorectal cancer (CRC) should undergo tumor screening for Lynch syndrome (LS). In 2011, leading cancer institutions and public health agencies created the Lynch Syndrome Screening Network (LSSN) in order to promote routine LS screening on all newly diagnosed CRCs and endometrial cancers (EC). The LSSN facilitates implementation of appropriate screening via shared resources, protocols and data through network collaboration. The LSSN website contains resources for institutions interested in initiating screening, including materials for program development, implementation and sustainability. The LSSN listserv gives providers access to experts in LS screening and implementation. The LSSN database will allow exploration of key gaps in implementation as a consortia-wide endeavor. To date, the LSSN's membership includes 85 institutions involved in the care of CRC patients and nine official partners such as national and state public health entities and other non-profit institutions. Nearly 80 % of the LSSN's members have already implemented routine or universal CRC and/or EC screening. LSSN serves to further the population health potential of universal LS screening through collaborative efforts and resources.

Colorectal cancer screening.

Mortality from colorectal cancer can be reduced by early diagnosis and by cancer prevention through polypectomy. These NCCN Guidelines for Colorectal Cancer Screening describe various colorectal screening modalities and recommended screening schedules for patients at average or increased risk of developing colorectal cancer. In addition, the guidelines provide recommendations for the management of patients with high-risk colorectal cancer syndromes, including Lynch syndrome. Screening approaches for Lynch syndrome are also described.

Serrated polyposis: colonic phenotype, extracolonic features, and familial risk in a large cohort.

BACKGROUND: Serrated polyposis is a poorly understood and likely underdiagnosed condition. Little is known regarding the colorectal cancer risk, extracolonic phenotype, and cause of serrated polyposis. OBJECTIVE: The aim of this study is to describe the clinical and family history features of a large cohort of individuals with serrated polyposis. DESIGN: This is a retrospective cohort study from 2 prospectively collected registries. PATIENTS: Patients meeting the updated 2010 World Health Organization criteria for serrated polyposis were included. MAIN OUTCOME MEASURES: We report descriptive statistics for clinical and family history factors. RESULTS: A total of 52 individuals met criteria for serrated polyposis. Of these, one had Lynch syndrome and was not included in the statistical analyses. Median age at serrated polyposis diagnosis was 51 years (range, 18-77). Twenty-four (47%) patients were male, and 25 (49%) had a history of smoking. Two hundred sixty-eight lower endoscopic procedures were performed; 42 (82%) patients had colorectal adenomas, 8 (16%) had a personal history of colorectal cancer (only 1 was diagnosed during follow-up), 12 (24%) had extracolonic tumors (4 had more than 1 primary tumor), and 19 (37%) reported a family history of colorectal cancer. Esophagogastroduodenoscopy in 30 individuals revealed only 1 (3%) with unexplained gastroduodenal polyps. No association was found between colorectal cancer diagnosis and sex, age at serrated polyposis diagnosis, extracolonic tumor, history of adenoma, or smoking status. LIMITATIONS: This was a retrospective study with no comparison groups. CONCLUSIONS: Gastroduodenal polyps are uncommon and likely not associated with serrated polyposis. Although extracolonic tumors were common in our cohort, it is still unclear whether these are associated with serrated polyposis. Our data, along with previous studies, support an association between serrated polyposis and smoking. Further work is still needed to clarify the effect of smoking on polyp development/progression in serrated polyposis.

Implementing screening for Lynch syndrome among patients with newly diagnosed colorectal cancer: summary of a public health/clinical collaborative meeting.

Lynch syndrome is the most common cause of inherited colorectal cancer, accounting for approximately 3% of all colorectal cancer cases in the United States. In 2009, an evidence-based review process conducted by the independent Evaluation of Genomic Applications in Practice and Prevention Working Group resulted in a recommendation to offer genetic testing for Lynch syndrome to all individuals with newly diagnosed colorectal cancer, with the intent of reducing morbidity and mortality in family members. To explore issues surrounding implementation of this recommendation, the Centers for Disease Control and Prevention convened a multidisciplinary working group meeting in September 2010. This article reviews background information regarding screening for Lynch syndrome and summarizes existing clinical paradigms, potential implementation strategies, and conclusions which emerged from the meeting. It was recognized that widespread implementation will present substantial challenges, and additional data from pilot studies will be needed. However, evidence of feasibility and population health benefits and the advantages of considering a public health approach were acknowledged. Lynch syndrome can potentially serve as a model to facilitate the development and implementation of population-level programs for evidence-based genomic medicine applications involving follow-up testing of at-risk relatives. Such endeavors will require multilevel and multidisciplinary approaches building on collaborative public health and clinical partnerships.

Identification of individuals at risk for Lynch syndrome using targeted evaluations and genetic testing: National Society of Genetic Counselors and the Collaborative Group of the Americas on Inherited Colorectal Cancer joint practice guideline.

Identifying individuals who have Lynch syndrome (LS) involves a complex diagnostic work up that includes taking a detailed family history and a combination of various genetic and immunohistochemical tests. The National Society of Genetic Counselors (NSGC) and the Collaborative Group of the Americas on Inherited Colorectal Cancer (CGA-ICC) have come together to publish this clinical practice testing guideline for the evaluation of LS. The purpose of this practice guideline is to provide guidance and a testing algorithm for LS as well as recommendations on when to offer testing. This guideline does not replace a consultation with a genetics professional. This guideline includes explanations in support of this and a summary of background data. While this guideline is not intended to serve as a review of LS, it includes a discussion of background information on LS, and cites a number of key publications which should be reviewed for a more in-depth understanding of LS. These guidelines are intended for genetic counselors, geneticists, gastroenterologists, surgeons, medical oncologists, obstetricians and gynecologists, nurses and other healthcare providers who evaluate patients for LS.

Universal Germline Panel Testing for Individuals With Pheochromocytoma and Paraganglioma Produces High Diagnostic Yield.

BACKGROUND: Practice guidelines to identify individuals with hereditary pheochromocytomas and paragangliomas (PPGLs) advocate for sequential gene testing strategy guided by specific clinical features and predate the routine use of multigene panel testing (MGPT). OBJECTIVE: To describe results of MGPT for hereditary PPGL in a clinically and ancestrally diverse cohort. SETTING: Commercial laboratory based in the United States. METHODS: Clinical data and test results were retrospectively reviewed in 1727 individuals who had targeted MGPT from August 2013 through December 2019 because of a suspicion of hereditary PPGL. RESULTS: Overall, 27.5% of individuals had a pathogenic or likely pathogenic variant (PV), 9.0% had a variant of uncertain significance, and 63.1% had a negative result. Most PVs were identified in SDHB (40.4%), followed by SDHD (21.1%), SDHA (10.1%), VHL (7.8%), SDHC (6.7%), RET (3.7%), and MAX (3.6%). PVs in FH, MEN1, NF1, SDHAF2, and TMEM127 collectively accounted for 6.5% of PVs. Clinical predictors of a PV included extra-adrenal location, early age of onset, multiple tumors, and positive family history of PPGL. Individuals with extra-adrenal PGL and a positive family history were the most likely to have a PV (85.9%). Restricting genetic testing to SDHB/C/D misses one-third (32.8%) of individuals with PVs. CONCLUSION: Our data demonstrate a high diagnostic yield in individuals with and without established risk factors, a low inconclusive result rate, and a substantial contribution to diagnostic yield from rare genes. These findings support universal testing of all individuals with PPGL and the use of concurrent MGPT as the ideal platform.

Hereditary and familial colon cancer.

Between 2% to 5% of all colon cancers arise in the setting of well-defined inherited syndromes, including Lynch syndrome, familial adenomatous polyposis, MUTYH-associated polyposis, and certain hamartomatous polyposis conditions. Each is associated with a high risk of colon cancer. In addition to the syndromes, up to one-third of colon cancers exhibit increased familial risk, likely related to inheritance. A number of less penetrant, but possibly more frequent susceptibility genes have been identified for this level of inheritance. Clarification of predisposing genes allows for accurate risk assessment and more precise screening approaches. This review examines the colon cancer syndromes, their genetics and management, and also the common familial colon cancers with current genetic advances and screening guidelines.

Delineating a new feature of constitutional mismatch repair deficiency (CMMRD) syndrome: breast cancer.

Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare autosomal recessive hereditary cancer condition, characterized by an exceptionally high risk of cancer, a propensity for childhood malignancies, and cutaneous features reminiscent of neurofibromatosis type 1 (NF1). We report on two sisters originally suspected of having CMMRD syndrome due to their history of colonic polyps and NF1 associated skin findings, both were subsequently found to have biallelic MSH6 mutations. After years of CMMRD syndrome follow-up, the proband was diagnosed with breast cancer at age 29, while her sister was diagnosed with a glioblastoma at age 27. Immunohistochemistry analysis on the breast tumor tissue revealed weak MSH6 protein staining. Exome sequencing revealed a hypermutated breast tumor and an ultra-hypermutated brain tumor. Multi-gene panel testing was also performed and revealed no additional mutations which might explain the proband's early onset breast cancer. This is the first documented case of breast cancer in an individual with CMMRD syndrome. We summarize the evidence supporting the possible association between breast cancer and biallelic MMR mutations. Healthcare providers should be aware of this possible association and follow-up appropriately for suspicious breast findings. In addition, this case highlights the need for frequent central nervous system screenings due to rapid progression of brain tumors.