Underutilization of Lynch syndrome screening in a multisite study of patients with colorectal cancer

PurposeThe aim of this study was to examine Lynch syndrome screening of patients with metastatic colorectal cancer in integrated health-care-delivery organizations.MethodsWe determined the availability of Lynch syndrome screening criteria and actual Lynch syndrome screening in the medical records of 1,188 patients diagnosed with metastatic colorectal cancer between 2004 and 2009 at seven institutions in the Cancer Research Network.ResultsWe found infrequent use of Lynch syndrome screening (41/1,188). Family history was available for 937 of the 1,188 patients (79%). There was sufficient information to assess Lynch syndrome risk using family history–based criteria in 719 of the 937 patients (77%) with family history documentation. In 391 individuals with a family history of a Lynch syndrome–associated cancer, 107 (27%) could not be evaluated due to missing information such as age of cancer onset. Eleven percent of patients who met the Bethesda criteria and 25% of individuals who met the Amsterdam II criteria were screened for Lynch syndrome. Recommended guidelines were adhered to during screening, but no testing method was preferred.ConclusionThe information required for Lynch syndrome screening decisions is routinely collected but seldom used. There is a critical gap between collection of family history and its use to guide Lynch syndrome screening, which may support a case for implementation of universal screening guidelines.Genet Med15 12, 933–940.     

Diagnosing hereditary cancer predisposition in men with prostate cancer

PurposeWe describe the pathogenic variant spectrum and identify predictors of positive results among men referred for clinical genetic testing for prostate cancer.MethodsOne thousand eight hundred twelve men with prostate cancer underwent clinical multigene panel testing between April 2012 and September 2017. Stepwise logistic regression determined the most reliable predictors of positive results among clinical variables reported on test requisition forms.ResultsA yield of 9.4–12.1% was observed among men with no prior genetic testing. In this group, the positive rate of BRCA1 and BRCA2 was 4.6%; the positive rate for the mismatch repair genes was 2.8%. Increasing Gleason score (odds ratio [OR] 1.19; 95% confidence interval [CI] 0.97–1.45); personal history of breast or pancreatic cancer (OR 3.62; 95% CI 1.37–9.46); family history of breast, ovarian, or pancreatic cancer (OR 2.32 95% CI 1.48–3.65); and family history of Lynch syndrome–associated cancers (OR 1.97; 95% CI 1.23–3.15) were predictors of positive results.ConclusionThese results support multigene panel testing as the primary genetic testing approach for hereditary prostate cancer and are supportive of recommendations for consideration of germline testing in men with prostate cancer. Expanding the criteria for genetic testing should be considered as many pathogenic variants are actionable for treatment of advanced prostate cancer.     

A clinical scoring system to identify patients with sebaceous neoplasms at risk for the Muir–Torre variant of Lynch syndrome

PurposeThe Muir–Torre syndrome variant of Lynch syndrome is characterized by the presence of sebaceous neoplasms (adenoma, epithelioma/sebaceoma, carcinoma) and Lynch syndrome–associated cancers (colon, endometrial, and others). Several clinical scoring systems have been developed to identify patients with colon cancer at high risk of Lynch syndrome. However, no such system has been described for patients presenting with sebaceous neoplasms.MethodsBased on logistic regression analysis, a scoring system was developed for patients with sebaceous neoplasm to identify those with the highest likelihood of having Muir–Torre syndrome. The final version of the scoring system included variables such as age at presentation of initial sebaceous neoplasm, total number of sebaceous neoplasms, personal history of a Lynch-related cancer, and family history of Lynch-related cancers.ResultsPatients with a score of 3 or more were more likely to have Muir–Torre syndrome (28 of 29 patients), those with a score of 2 had intermediate likelihood (12 of 20 patients), and no patient with a score of 0 or 1 was diagnosed with Muir–Torre syndrome.ConclusionThe Mayo Muir–Torre syndrome risk scoring system appears to identify whether patients who present with sebaceous neoplasms are in need of further Lynch syndrome evaluation using easily ascertained clinical information. Abnormal mismatch repair gene immunohistochemistry of a sebaceous neoplasm is a poor predictor in regard to diagnosing Lynch syndrome.     

Immunohistochemistry staining for the mismatch repair proteins in the clinical care of patients with colorectal cancer

PurposeThe Ohio State University was one of the first medical centers to begin routinely performing immunohistochemical staining for the four mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2) on all newly diagnosed patients with colorectal cancer. The results of implementing this testing on a clinical basis are critically assessed.MethodsFrom March 1, 2006, to March 31, 2008, 270 newly diagnosed colorectal cancer tumors received immunohistochemical staining for MLH1, MSH2, MSH6, and PMS2. If any stain was absent, the cancer genetic counselors were alerted, so that they could contact the patient. A follow-up genetic consultation was recommended for all patients with any stain absent other than MLH1 and to patients with absence of MLH1 ± PMS2 who were diagnosed younger than 60 years had a multiple Lynch syndrome-associated cancers or had a first-degree relative with colorectal cancer or endometrial cancer. Those attending the genetic consultation were offered appropriate follow-up testing.ResultsThere were 57 (21.1%) cases with abnormal immunohistochemical results. Genetics was able to contact 54 (94.7%) of these patients. It was determined that 34 (62.9%) of these 54 patients should be referred for a cancer genetics consultation, however, only nine (26.5%) made an appointment. Seven of the nine underwent additional testing, which was informative in five of the patients. Two (0.7%) new cases of Lynch syndrome were diagnosed and three patients were found to have proven/probable MLH1 promoter methylation.ConclusionsRoutine immunohistochemical of the mismatch repair proteins on all newly diagnosed patients with colorectal cancer can be implemented clinically, however, patient uptake of follow-up genetic consultation is lower than expected.     

Novel MLH1 duplication identified in Colombian families with Lynch syndrome

PurposeLynch syndrome accounts for 2–4% of all colorectal cancer, and is mainly caused by germline mutations in the DNA mismatch repair genes. Our aim was to characterize the genetic mutation responsible for Lynch syndrome in an extensive Colombian family and to study its prevalence in Antioquia.MethodsA Lynch syndrome family fulfilling Amsterdam criteria II was studied by immunohistochemistry and by multiplex ligation-dependent probe amplification (MLPA). Results were confirmed by additional independent MLPA, Southern blotting, and sequencing.ResultsIndex case tumor immunohistochemistry results were MLH1−, MSH2+, MSH6+, and PMS2−. MLPA analysis detected a duplication of exons 12 and 13 of MLH1. This mutation was confirmed and characterized precisely to span 4219 base pairs. Duplication screening in this family led to the identification of six additional carriers and 13 noncarriers. We also screened 123 early-onset independent colorectal cancer cases from the same area and identified an additional unrelated carrier.ConclusionA novel duplication of exons 12 and 13 of the MLH1 gene was detected in two independent Lynch syndrome families from Colombia. A putative founder effect and prescreening Lynch syndrome Antioquia families for this specific mutation before thorough mismatch repair mutational screening could be suggested. Genet Med 2011:13(2):155–160.     

Implementation of routine screening for Lynch syndrome in university and safety-net health system settings: successes and challenges

PurposeRoutine screening for evidence of DNA mismatch repair abnormalities can identify colorectal cancer patients with Lynch syndrome, but impact in usual care settings requires study. After implementing routine screening at our university and safety-net health systems as usual practice, our aims were to determine outcomes, including screening process quality.MethodsWe conducted a retrospective cohort study from 1 May 2010 to 1 May 2011. Screening included reflexive immunohistochemistry to evaluate DNA mismatch repair protein expression for patients with colorectal cancer aged ≤70 years, with a cancer genetics team following up results. Screening outcomes, as well as challenges to a high-quality screening process were evaluated.ResultsWe included 129 patients (mean age 56 years, 36% female); 100 had immunohistochemistry screening completed. Twelve patients had abnormal immunohistochemistry: four with definite Lynch syndrome, four with probable Lynch syndrome, and three without Lynch syndrome; one patient had an incomplete work-up. Lynch syndrome was confirmed for 6/13 asymptomatic relatives tested. Screening process quality was optimal for 77.5% of patients. Barriers to optimal quality screening included ensuring reflexive immunohistochemistry completion, complete follow-up of abnormal immunohistochemistry, and timely incorporation of results into clinical decision making.ConclusionUsual care implementation of routine screening for Lynch syndrome can result in significant rates of detection, even in a largely safety-net setting. To optimize implementation, challenges to high-quality Lynch syndrome screening, such as ensuring reflexive screening completion and clinically indicated genetic testing and follow-up for abnormal screens, must be identified and addressed.Genet Med15 12, 925–932.     

Performance of PREMM1,2,6, MMRpredict,and MMRpro in detecting Lynch syndrome among endometrial cancer cases

PurposeLynch syndrome accounts for 2–5% of endometrial cancer cases. Lynch syndrome prediction models have not been evaluated among endometrial cancer cases.MethodsArea under the receiver operating curve (AUC), sensitivity and specificity of PREMM_1,2,6, MMRpredict, and MMRpro scores were assessed among 563 population-based and 129 clinic-based endometrial cancer cases.ResultsA total of 14 (3%) population-based and 80 (62%) clinic-based subjects had pathogenic mutations. PREMM_1,2,6, MMRpredict, and MMRpro were able to distinguish mutation carriers from noncarriers (AUC of 0.77, 0.76, and 0.77, respectively), among population-based cases. All three models had lower discrimination for the clinic-based cohort, with AUCs of 0.67, 0.64, and 0.54, respectively. Using a 5% cutoff, sensitivity and specificity were as follows: PREMM_1,2,6, 93% and 5% among population-based cases and 99% and 2% among clinic-based cases; MMRpredict, 71% and 64% for the population-based cohort and 91% and 0% for the clinic-based cohort; and MMRpro, 57% and 85% among population-based cases and 95% and 10% among clinic-based cases.ConclusionCurrently available prediction models have limited clinical utility in determining which patients with endometrial cancer should undergo genetic testing for Lynch syndrome. Immunohistochemical analysis and microsatellite instability testing may be the best currently available tools to screen for Lynch syndrome in endometrial cancer patients.Genet Med advance online publication 8 March 2012     

Recommendations from the EGAPP Working Group: genetic testing strategies in newly diagnosed individuals with colorectal cancer aimed at reducing morbidity and mortality from Lynch syndrome in relatives

Summary of RecommendationsThe Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group found sufficient evidence to recommend offering genetic testing for Lynch syndrome to individuals with newly diagnosed colorectal cancer to reduce morbidity and mortality in relatives. We found insufficient evidence to recommend a specific genetic testing strategy among the several examined.RationaleGenetic testing to detect Lynch syndrome in individuals with newly diagnosed colorectal cancer (CRC) is proposed as a strategy to reduce CRC morbidity and mortality in their relatives (see Clinical Considerations section for definition of Lynch syndrome). The EGAPP Working Group (EWG) constructed a chain of evidence that linked genetic testing for Lynch syndrome in patients with newly diagnosed CRC with improved health outcomes in their relatives. We found that assessing patients who have newly diagnosed CRC with a series of genetic tests could lead to the identification of Lynch syndrome. Relatives of patients with Lynch syndrome could then be offered genetic testing, and, where indicated, colorectal, and possibly endometrial, cancer surveillance, with the expectation of improved health outcome. The EWG concluded that there is moderate certainty that such a testing strategy would provide moderate population benefit.Analytic ValidityThe EWG found adequate evidence to conclude that the analytic sensitivity and specificity for preliminary and diagnostic tests were high.Clinical ValidityAfter accounting for the specific technologies and numbers of markers used, the EWG found at least adequate evidence to describe the clinical sensitivity and specificity for three preliminary tests, and for four selected testing strategies. These measures of clinical validity varied with each test and each strategy (see Clinical Considerations section).Clinical UtilityThe EWG found adequate evidence for testing uptake rates, adherence to recommended surveillance activities, number of relatives approachable, harms associated with additional follow-up, and effectiveness of routine colonoscopy. This chain of evidence supported the use of genetic testing strategies to reduce morbidity/mortality in relatives with Lynch syndrome. Several genetic testing strategies were potentially effective, but none was clearly superior. The evidence for or against effectiveness of identifying mismatch repair (MMR) gene mutations in reducing endometrial cancer morbidity or mortality was inadequate.Contextual IssuesCRC is a common disease responsible for an estimated 52,000 deaths in the United States in 2007. In about 3% of newly diagnosed CRC, the underlying cause is a mutation in a MMR gene (Lynch syndrome) that can be reliably identified with existing laboratory tests. Relatives inheriting the mutation have a high (about 45% by age 70) risk of developing CRC. Evidence suggests these relatives will often accept testing and increased surveillance.     

The cost-effectiveness of genetic testing strategies for Lynch syndrome among newly diagnosed patients with colorectal cancer

PurposeTo estimate the cost-effectiveness of genetic testing strategies to identify Lynch syndrome among newly diagnosed patients with colorectal cancer and to offer targeted testing to relatives of patients with Lynch syndrome.MethodsWe calculated incremental costs per life-year saved for universal testing relative to no testing and age-targeted testing for strategies that use preliminary genetic tests (immunohistochemistry or microsatellite instability) of tumors followed by sequencing of mismatch repair genes. We also calculated incremental cost-effectiveness ratios for pairs of testing strategies.ResultsStrategies to test for Lynch syndrome in newly diagnosed colorectal tumors using preliminary tests before gene sequencing have incremental cost-effectiveness ratios of ≤$45,000 per life-year saved compared with no testing and ≤$75,000 per life-year saved compared with testing restricted to patients younger than 50 years. The lowest cost testing strategies, using immunohistochemistry as a preliminary test, cost ≤$25,000 per life-year saved relative to no testing and ≤$40,000 per life-year saved relative to testing only patients younger than 50 years. Other testing strategies have incremental cost-effectiveness ratios ≥$700,000 per life-year saved relative to the lowest cost strategies. Increasing the number of relatives tested would improve cost-effectiveness.ConclusionLaboratory-based strategies using preliminary tests seem cost-effective from the US health care system perspective. Universal testing detects nearly twice as many cases of Lynch syndrome as targeting younger patients and has an incremental cost-effectiveness ratio comparable with other preventive services. This finding provides support for a recent US recommendation to offer testing for Lynch syndrome to all newly diagnosed patients with colorectal cancer.     

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

PurposeBiallelic 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.MethodsCumulative 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.ResultsThe 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.ConclusionOur 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.     

The prevalence of adenoviral conjunctivitis at the Clinical Hospital of the State University of Campinas,Brazil

OBJECTIVES:Viral conjunctivitis is a common, highly contagious disease that is often caused by an adenovirus. The aim of this study was to evaluate the prevalence of adenoviral conjunctivitis by analyzing data from a prospective clinical study of 122 consecutively enrolled patients who were treated at the Clinical Hospital of the State University of Campinas (UNICAMP) after a clinical diagnosis of infectious conjunctivitis between November 2011 and June 2012.METHODS:Polymerase chain reaction was used to evaluate all cases of clinically diagnosed infectious conjunctivitis and based on the laboratory findings, the prevalence of adenoviral infections was determined. The incidence of subepithelial corneal infiltrates was also investigated.RESULTS:Of the 122 patients with acute infectious conjunctivitis included, 72 had positive polymerase chain reaction results for adenoviruses and 17 patients developed subepithelial corneal infiltrates (13.93%).CONCLUSIONS:The polymerase chain reaction revealed that the prevalence of adenoviral conjunctivitis was 59% in all patients who presented with a clinical diagnosis of infectious conjunctivitis from November 2011 to June 2012. The prevalence of adenoviral conjunctivitis in the study population was similar to its prevalence in other regions of the world.     

The Manchester International Consensus Group recommendations for the management of gynecological cancers in Lynch syndrome

PurposeThere are no internationally agreed upon clinical guidelines as to which women with gynecological cancer would benefit from Lynch syndrome screening or how best to manage the risk of gynecological cancer in women with Lynch syndrome. The Manchester International Consensus Group was convened in April 2017 to address this unmet need. The aim of the Group was to develop clear and comprehensive clinical guidance regarding the management of the gynecological sequelae of Lynch syndrome based on existing evidence and expert opinion from medical professionals and patients.MethodsStakeholders from Europe and North America worked together over a two-day workshop to achieve consensus on best practice.ResultsGuidance was developed in four key areas: (1) whether women with gynecological cancer should be screened for Lynch syndrome and (2) how this should be done, (3) whether there was a role for gynecological surveillance in women at risk of Lynch syndrome, and (4) what preventive measures should be recommended for women with Lynch syndrome to reduce their risk of gynecological cancer.ConclusionThis document provides comprehensive clinical guidance that can be referenced by both patients and clinicians so that women with Lynch syndrome can expect and receive appropriate standards of care.     

Low risk of solid tumors in persons with Down syndrome

PurposeThe aim of this study was to investigate cancer incidence in a large cohort of persons with Down syndrome.MethodsDown syndrome was identified from the Danish Cytogenetic Register. Cancer occurrence was identified by linkage to the Danish Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated based on observed and expected numbers from rates for all Danish residents. The cohort consisted of 3,530 persons with Down syndrome contributing 89,570 person-years at risk.ResultsAcute leukemia risk was highest from 1–4 years of age and remained elevated until age 30. The overall risk of solid tumors was decreased (SIR 0.45; 95% CI 0.34–0.59), especially in persons 50 years or older (SIR 0.27; 95% CI 0.16–0.43). We found a significantly lower risk of lung cancer (SIR 0.10; 95% CI 0.00–0.56), breast cancer (SIR 0.16; 95% CI 0.03–0.47), and cervical cancer (SIR 0.0; 95% CI 0.00–0.77). Testicular cancer was the only solid tumor with an increased SIR (2.9; 95% CI 1.6–4.8).ConclusionsThe risk of all major groups of solid tumors was decreased, except testicular cancer. Altered screening strategies should be considered for persons with Down syndrome. This unusual pattern of cancer occurrence may help understanding carcinogenesis in the general population.Genet Med 18 11, 1151–1157.     

Protein expression profiles of deoxyribonucleic acid mismatch repair genes: Association with clinicopathological characteristics of Malaysian Lynch syndrome patients

Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, accounts for approximately 1–5% of all colorectal cancers. Germline mutations in a group of deoxyribonucleic acid (DNA) mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS1, and PMS2) are responsible for Lynch syndrome cases. This study focuses on the determination of MMR (MLH1, MSH2, MSH6, and PMS2) protein expression profile by immunohistochemical analysis and its association with clinicopathological characteristics in clinically diagnosed Malaysian Lynch syndrome patients. Fifty patients who fulfilled any of the revised Bethesda Guidelines criteria were recruited from four collaborating centers in Malaysia. Clinicopathological information of clinically diagnosed Lynch syndrome cases that underwent bowel resection was reviewed. Immunohistochemical analysis for MLH1, MSH2, MSH6, and PMS2 proteins were performed on paraffin-embedded carcinomatous tissues. Colorectal cancer protein expression analysis for MLH1, MSH2, MSH6, and PMS2 antigens showed absence of expression of any MMR proteins in 18 out of 50 clinically diagnosed Lynch syndrome patients (36.0%). There was a significant association between abnormal MMR protein expression with tumor size (p = 0.012), histological differentiation of cancers (p = 0.012), and growth pattern of tumor (p = 0.01). Abnormal expression of MMR protein in colorectal cancers in clinically diagnosed Lynch syndrome patients was associated with specific clinicopathological characteristics such as tumor size, histological differentiation of cancers, and growth pattern of tumor. Immunohistochemical analysis proved to be an advantageous pre-screening tool for Lynch syndrome in Malaysian patients and highly predictive of a germline mutation in DNA MMR genes.     

ACMG technical standards and guidelines for genetic testing for inherited colorectal cancer (Lynch syndrome,familial adenomatous polyposis,and MYH-associated polyposis)

Lynch syndrome, familial adenomatous polyposis, and Mut Y homolog (MYH)-associated polyposis are three major known types of inherited colorectal cancer, which accounts for up to 5% of all colon cancer cases. Lynch syndrome is most frequently caused by mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 and is inherited in an autosomal dominant manner. Familial adenomatous polyposis is manifested as colonic polyposis caused by mutations in the APC gene and is also inherited in an autosomal dominant manner. Finally, MYH-associated polyposis is caused by mutations in the MUTYH gene and is inherited in an autosomal recessive manner but may or may not be associated with polyps. There are variants of both familial adenomatous polyposis (Gardner syndrome—with extracolonic features—and Turcot syndrome, which features medulloblastoma) and Lynch syndrome (Muir–Torre syndrome features sebaceous skin carcinomas, and Turcot syndrome features glioblastomas). Although a clinical diagnosis of familial adenomatous polyposis can be made using colonoscopy, genetic testing is needed to inform at-risk relatives. Because of the overlapping phenotypes between attenuated familial adenomatous polyposis, MYH-associated polyposis, and Lynch syndrome, genetic testing is needed to distinguish among these conditions. This distinction is important, especially for women with Lynch syndrome, who are at increased risk for gynecological cancers. Clinical testing for these genes has progressed rapidly in the past few years with advances in technologies and the lower cost of reagents, especially for sequencing. To assist clinical laboratories in developing and validating testing for this group of inherited colorectal cancers, the American College of Medical Genetics and Genomics has developed the following technical standards and guidelines. An algorithm for testing is also proposed.Genet Med16 1, 101–116.     

Patients with colorectal cancer associated with Lynch syndrome and MLH1 promoter hypermethylation have similar prognoses

PurposeMismatch repair–deficient (dMMR) colorectal cancer (CRC) is caused by Lynch syndrome (LS) in 3% and sporadic inactivation of MLH1 by hypermethylation (MLH1-hm) in 12% of cases. It is not clear whether outcomes between LS-associated and MLH1-hm CRC differ. The objective of this study was to explore differences in clinical factors and outcomes in these two groups.MethodsPatients with dMMR CRC identified by immunohistochemistry staining and treated at a single institution from 1998 to 2012 were included. MLH1-hm was established with BRAF mutational analysis or hypermethylation testing. Patients’ charts were accessed for information on pathology, germ-line MMR mutation testing, and clinical course.ResultsA total of 143 patients had CRC associated with LS (37 patients, 26%) or MLH1-hm (106 patients, 74%). Patients with LS were younger, more often male, presented more often with stage III disease, and had more metachronous disease than patients with MLH1-hm tumors. There was no difference in cancer-specific survival (CSS) between the groups; overall survival was longer in patients with LS, but this difference was minimal after adjusting for age and stage at diagnosis.ConclusionCSS did not differ in LS-associated CRC compared with MLH1-hm CRC, suggesting that they carry a similar prognosis.Genet Med 18 9, 863–868.     

Is it all Lynch syndrome?: An assessment of family history in individuals with mismatch repair–deficient tumors

PurposeMismatch repair-deficient (MMRD) colorectal cancer (CRC) and endometrial cancer (EC) may be suggestive of Lynch syndrome (LS). LS can be confirmed only by positive germ-line testing. It is unclear if individuals with MMRD tumors but no identifiable cause (MMRD+/germ-line−) have LS. Because LS is hereditary, individuals with LS are expected to have family histories of LS-related tumors. Our study compared the family histories of MMRD+/germ-line− CRC and/or EC patients with LS CRC and/or EC patients.MethodsA total of 253 individuals with an MMRD CRC or EC from one institution were included for analysis in one of four groups: LS; MMRD+/germ-line−; MMRD tumor with variant of uncertain significance (MMRD+/VUS); and sporadic MSI-H (MMRD tumor with MLH1 promoter hypermethylation or BRAF mutation). Family histories were analyzed utilizing MMRpro and PREMM_1,2,6. Kruskal–Wallis tests were used to compare family history scores.ResultsMMRD+/germ-line− individuals had significantly lower median family history scores (MMRpro = 8.1, PREMM_1,2,6 = 7.3) than did LS individuals (MMRpro = 89.8, PREMM_1,2,6 = 26.1, P < 0.0001).ConclusionMMRD+/germ-line− individuals have less suggestive family histories of LS than individuals with LS. These results imply that MMRD+/germ-line− individuals may not all have LS. This finding highlights the need to determine other causes of MMRD tumors so that these patients and their families can be accurately counseled regarding screening and management.Genet Med 17 6, 476–484.     

MSH6 and PMS2 germ-line pathogenic variants implicated in Lynch syndrome are associated with breast cancer

PurposeAn association of Lynch syndrome (LS) with breast cancer has been long suspected; however, there have been insufficient data to address this question for each of the LS genes individually.MethodsWe conducted a retrospective review of personal and family history in 423 women with pathogenic or likely pathogenic germ-line variants in MLH1 (N = 65), MSH2 (N = 94), MSH6 (N = 140), or PMS2 (N = 124) identified via clinical multigene hereditary cancer testing. Standard incidence ratios (SIRs) of breast cancer were calculated by comparing breast cancer frequencies in our study population with those in the general population (Surveillance, Epidemiology, and End Results 18 data).ResultsWhen evaluating by gene, the age-standardized breast cancer risks for MSH6 (SIR = 2.11; 95% confidence interval (CI), 1.56–2.86) and PMS2 (SIR = 2.92; 95% CI, 2.17–3.92) were associated with a statistically significant risk for breast cancer whereas no association was observed for MLH1 (SIR = 0.87; 95% CI, 0.42–1.83) or MSH2 (SIR = 1.22; 95% CI, 0.72–2.06).ConclusionOur data demonstrate that two LS genes, MSH6 and PMS2, are associated with an increased risk for breast cancer and should be considered when ordering genetic testing for individuals who have a personal and/or family history of breast cancer.     

Cancer risks by gene,age, and gender in 6350 carriers of pathogenic mismatch repair variants: findings from the Prospective Lynch Syndrome Database

PurposePathogenic variants affecting MLH1, MSH2, MSH6, and PMS2 cause Lynch syndrome and result in different but imprecisely known cancer risks. This study aimed to provide age and organ-specific cancer risks according to gene and gender and to determine survival after cancer.MethodsWe conducted an international, multicenter prospective observational study using independent test and validation cohorts of carriers of class 4 or class 5 variants. After validation the cohorts were merged providing 6350 participants and 51,646 follow-up years.ResultsThere were 1808 prospectively observed cancers. Pathogenic MLH1 and MSH2 variants caused high penetrance dominant cancer syndromes sharing similar colorectal, endometrial, and ovarian cancer risks, but older MSH2 carriers had higher risk of cancers of the upper urinary tract, upper gastrointestinal tract, brain, and particularly prostate. Pathogenic MSH6 variants caused a sex-limited trait with high endometrial cancer risk but only modestly increased colorectal cancer risk in both genders. We did not demonstrate a significantly increased cancer risk in carriers of pathogenic PMS2 variants. Ten-year crude survival was over 80% following colon, endometrial, or ovarian cancer.ConclusionManagement guidelines for Lynch syndrome may require revision in light of these different gene and gender-specific risks and the good prognosis for the most commonly associated cancers.