Prediction of MLH1 and MSH2 mutations in Lynch syndrome

Landscape of germline pathogenic variants in patients with dual primary breast and lung cancer

BACKGROUND

Cancer predisposition is most often studied in the context of single cancers. However, inherited cancer predispositions can also give rise to multiple primary cancers. Yet, there is a paucity of studies on genetic predisposition in multiple primary cancers, especially those outside of well-defined cancer predisposition syndromes. This study aimed to identify germline variants associated with dual primary cancers of the breast and lung.

METHODS

Exome sequencing was performed on germline DNA from 55 Singapore patients (52 [95%] never-smokers) with dual primaries in the breast and lung, confirmed by histopathology. Using two large control cohorts: the local SG10K_Health (n = 9770) and gnomAD non-cancer East Asians (n = 9626); and two additional local case cohorts of early-onset or familial breast cancer (n = 290), and lung cancer (n = 209), variants were assessed for pathogenicity in accordance with ACMG/AMP guidelines. In particular, comparisons were made with known pathogenic or likely pathogenic variants in the ClinVar database, pathogenicity predictions were obtained from in silico prediction software, and case-control association analyses were performed.

RESULTS

Altogether, we identified 19 pathogenic or likely pathogenic variants from 16 genes, detected in 17 of 55 (31%) patients. Six of the 19 variants were identified using ClinVar, while 13 variants were classified pathogenic or likely pathogenic using ACMG/AMP guidelines. The 16 genes include well-known cancer predisposition genes such as BRCA2, TP53, and RAD51D; but also lesser known cancer genes EXT2, WWOX, GATA2, and GPC3. Most of these genes are involved in DNA damage repair, reaffirming the role of impaired DNA repair mechanisms in the development of multiple malignancies. These variants warrant further investigations in additional populations.

CONCLUSIONS

We have identified both known and novel variants significantly enriched in patients with primary breast and lung malignancies, expanding the body of known cancer predisposition variants for both breast and lung cancer. These variants are mostly from genes involved in DNA repair, affirming the role of impaired DNA repair in the predisposition and development of multiple cancers.

Updates in gynecologic care for individuals with lynch syndrome

Lynch syndrome is an autosomal dominant hereditary cancer syndrome caused by germline pathogenic variants (PVs) in DNA mismatch repair genes (MLH1, MSH2, PMS2, MSH6) or the EPCAM gene. It is estimated to affect 1 in 300 individuals and confers a lifetime risk of cancer of 10-90%, depending on the specific variant and type of cancer. Lynch syndrome is the most common cause of inherited colorectal cancer, but for women, endometrial cancer is more likely to be the sentinel cancer. There is also evidence that certain PVs causing Lynch syndrome confer an increased risk of ovarian cancer, while the risk of ovarian cancer in others is not well defined. Given this, it is essential for the practicing gynecologist and gynecologic oncologist to remain up to date on the latest techniques in identification and diagnosis of individuals with Lynch syndrome as well as evidence-based screening and risk reduction recommendations for those impacted. Furthermore, as the landscape of gynecologic cancer treatment shifts towards treatment based on molecular classification of tumors, knowledge of targeted therapies well-suited for mismatch repair deficient Lynch tumors will be crucial. The objective of this review is to highlight recent updates in the literature regarding identification and management of individuals with Lynch syndrome as it pertains to endometrial and ovarian cancers to allow gynecologic providers the opportunity to both prevent and identify Lynch-associated cancers earlier, thereby reducing the morbidity and mortality of the syndrome.

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.

A validation of models for prediction of pathogenic variants in mismatch repair genes

PURPOSE

Models used to predict the probability of an individual having a pathogenic homozygous or heterozygous variant in a mismatch repair gene, such as MMRpro, are widely used. Recently, MMRpro was updated with new colorectal cancer penetrance estimates. The purpose of this study was to evaluate the predictive performance of MMRpro and other models for individuals with a family history of colorectal cancer.

METHODS

We performed a validation study of 4 models, Leiden, MMRpredict, PREMM5, and MMRpro, using 784 members of clinic-based families from the United States. Predicted probabilities were compared with germline testing results and evaluated for discrimination, calibration, and predictive accuracy. We analyzed several strategies to combine models and improve predictive performance.

RESULTS

MMRpro with additional tumor information (MMRpro+) and PREMM5 outperformed the other models in discrimination and predictive accuracy. MMRpro+ was the best calibrated with an observed to expected ratio of 0.98 (95% CI = 0.89-1.08). The combination models showed improvement over PREMM5 and performed similar to MMRpro+.

CONCLUSION

MMRpro+ and PREMM5 performed well in predicting the probability of having a pathogenic homozygous or heterozygous variant in a mismatch repair gene. They serve as useful clinical decision tools for identifying individuals who would benefit greatly from screening and prevention strategies.

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.

Identification of Lynch Syndrome

Lynch syndrome (LS) is an autosomal dominant hereditary cancer syndrome caused by pathogenic germline variants (PGV) in any of the 4 DNA mismatch repair (MMR) genes, MLH1, MSH2, MSH6, and PMS2, or deletions in EPCAM. LS leads to an increased risk of intestinal and extraintestinal cancers, of which colorectal and endometrial cancers are the most common. Individuals at risk for LS can be identified by using clinical criteria, prediction models, and universal tumor testing. Understanding each of these tools, including limitations and mimics of LS, is essential to the early identification of at-risk individuals.

Prediction of overall survival in patients with Stage I esophageal cancer: A novel web-based calculator

BACKGROUND AND AIMS

In this study, we aimed to develop a convenient web-based calculator to predict the overall survival (OS) of patients with Stage I esophageal cancer (EC).

METHODS

Data of 1664 patients, between 2004 and 2015, were extracted from the Surveillance, Epidemiology, and End Results database. Least absolute shrinkage and selection operator regression was employed to sift variables; subsequently, Cox proportional hazards regression model was built. We applied the enhanced bootstrap validation to appraise the discrimination and calibration of the model. Clinical benefit was measured using decision curve analysis (DCA). Thereafter, a web-based calculator based on the model, which could be used to predict the 1-, 3-, and 5-year OS rates, was developed.

RESULTS

Race, age, histologic type, grade, N stage, and therapeutic methods were selected. C-indices of the prediction model in the training and validation groups were 0.726 (95% confidence interval [CI], 0.679-0.773) and 0.724 (95% CI, 0.679-0.769), respectively. Calibration curves showed good agreement between the groups. The DCA demonstrated that the prediction model is clinically useful.

CONCLUSIONS

The prediction model we developed showed a good performance in calculating the OS rates in patients with Stage I EC. The web-based calculator is available at https://championship.shinyapps.io/dynnomapp/.

Utilization of breast cancer risk prediction models by cancer genetic counselors in clinical practice predominantly in the United States

Risk assessment in cancer genetic counseling is essential in identifying individuals at high risk for developing breast cancer to recommend appropriate screening and management options. Historically, many breast cancer risk prediction models were developed to calculate an individual's risk to develop breast cancer or to carry a pathogenic variant in the BRCA1 or BRCA2 genes. However, how or when genetic counselors use these models in clinical settings is currently unknown. We explored genetic counselors' breast cancer risk model usage patterns including frequency of use, reasons for using or not using models, and change in usage since the adoption of multi-gene panel testing. An online survey was developed and sent to members of the National Society of Genetic Counselors; board-certified genetic counselors whose practice included cancer genetic counseling were eligible to participate in the study. The response rate was estimated at 23% (243/1,058), and respondents were predominantly working in the United States. The results showed that 93% of all respondents use at least one breast cancer risk prediction model in their clinical practice. Among the six risk models selected for the study, the Tyrer-Cuzick (IBIS) model was used most frequently (95%), and the BOADICEA model was used least (40%). Determining increased or decreased surveillance and breast MRI eligibility were the two most common reasons for most model usage, while time consumption and difficulty in navigation were the two most common reasons for not using models. This study provides insight into perceived benefits and limitations of risk models in clinical use in the United States, which may be useful information for software developers, genetic counseling program curriculum developers, and currently practicing cancer genetic counselors.

miRGTF-net: Integrative miRNA-gene-TF network analysis reveals key drivers of breast cancer recurrence

Analysis of regulatory networks is a powerful framework for identification and quantification of intracellular interactions. We introduce miRGTF-net, a novel tool for construction of miRNA-gene-TF networks. We consider multiple transcriptional and post-transcriptional interaction types, including regulation of gene and miRNA expression by transcription factors, gene silencing by miRNAs, and co-expression of host genes with their intronic miRNAs. The underlying algorithm uses information on experimentally validated interactions as well as integrative miRNA/mRNA expression profiles in a given set of samples. The latter ensures simultaneous tissue-specificity and biological validity of interactions. We applied miRGTF-net to paired miRNA/mRNA-sequencing data of breast cancer samples from The Cancer Genome Atlas (TCGA). Together with topological analysis of the constructed network we showed that considered players can form reliable prognostic gene signatures for ER-positive breast cancer. A number of signatures demonstrated remarkably high accuracy on transcriptomic data obtained by both microarrays and RNA sequencing from several independent patient cohorts. Furthermore, an essential part of prognostic genes were identified as direct targets of transcription factor E2F1. The putative interplay between estrogen receptor alpha and E2F1 was suggested as a potential recurrence factor in patients treated with tamoxifen. Source codes of miRGTF-net are available at GitHub (https://github.com/s-a-nersisyan/miRGTF-net).

Diagnosis of Lynch Syndrome and Strategies to Distinguish Lynch-Related Tumors from Sporadic MSI/dMMR Tumors

Simple Summary

Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific, as most of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Therefore, the identification of MSI/dMMR requires additional diagnostic tools to identify LS. In this review, we address the hallmarks of LS and present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with current strategies, which should be taken into account in order to improve the diagnosis of LS.

Abstract

Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific to it, as approximately 80% of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Methods leading to the diagnosis of LS have considerably evolved in recent years and so have tumoral tests for LS screening and for the discrimination of LS-related to MSI-sporadic tumors. In this review, we address the hallmarks of LS, including the clinical, histopathological, and molecular features. We present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with the current strategies, which should be taken into account to improve the diagnosis of LS and avoid inappropriate clinical management.

Development and validation of a prediction model for airflow obstruction in older Chinese: Guangzhou Biobank Cohort Study

OBJECTIVE

To develop and validate a prediction model for airflow obstruction (AO) in older Chinese.

METHODS

DESIGN

Multivariable logistic regression analysis in large population cohort of Chinese aged ≥50 years.

PARTICIPANTS

Model development: 8762 Chinese aged ≥50 years were selected from the early phase recruits to the Guangzhou Biobank Cohort Study (GBCS) (recruited from September 2003 to May 2006). Internal validation: 100 bootstrap samples drawn with replacement from the development sample. External validation: 8395 Chinese aged ≥50 years from later phase GBCS (recruited from September 2006 to January 2008).

OUTCOMES

AO was defined by a forced expiratory volume in 1 s/forced vital capacity ratio < lower limits of normal.

RESULTS

839 (9.6%) and 764 (9.1%) individuals had AO in the development and temporal validation samples respectively. The predictors in the prediction model included sex, age, body mass index groups, smoking status, presence of respiratory symptoms, and history of asthma. Model development and validation was stratified by sex. Model performance including calibration (calibration-in-the-large -0.017 vs. -0.157; and calibration slope 0.88 vs. 1.02), discrimination (C-statistic 0.72 vs. 0.63 with 95% confidence interval 0.69-0.75 vs. 0.62-0.73) and clinical usefulness (decision curve analysis) in the external temporal validation sample were more satisfactory in men than that in women. Prediction models with risk thresholds (13% in men and 7% in women) and easy-to-use nomograms were developed to assess the probability of AO.

CONCLUSION

The diagnostic models based on readily available epidemiologic and clinical information with satisfactory performance can assist physicians to identify older individuals at high risk of AO and may improve the efficiency of spirometry for active case finding. Further validation beyond the Chinese population is warranted.

Hereditary Predisposition to Prostate Cancer: From Genetics to Clinical Implications

Prostate cancer (PrCa) ranks among the top five cancers for both incidence and mortality worldwide. A significant proportion of PrCa susceptibility has been attributed to inherited predisposition, with 10-20% of cases expected to occur in a hereditary/familial context. Advances in DNA sequencing technologies have uncovered several moderate- to high-penetrance PrCa susceptibility genes, most of which have previously been related to known hereditary cancer syndromes, namely the hereditary breast and ovarian cancer (BRCA1, BRCA2, ATM, CHEK2, and PALB2) and Lynch syndrome (MLH1, MSH2, MSH6, and PMS2) genes. Additional candidate genes have also been suggested, but further evidence is needed to include them in routine genetic testing. Recommendations based on clinical features, family history, and ethnicity have been established for more cost-efficient genetic testing of patients and families who may be at an increased risk of developing PrCa. The identification of alterations in PrCa predisposing genes may help to inform screening strategies, as well as treatment options, in the metastatic setting. This review provides an overview of the genetic basis underlying hereditary predisposition to PrCa, the current genetic screening recommendations, and the implications for clinical management of the disease.

Lynch Syndrome Germline Mutations in Breast Cancer: Next Generation Sequencing Case-Control Study of 1,263 Participants

Genome instability—the increased tendency of acquiring mutations in the genome and ability of a cell to tolerate high mutation burden—is one of the drivers of cancer. Genome instability results from many causes including defects in DNA repair systems. Previously, it has been shown that germline pathogenic mutations in DNA Mismatch Repair (MMR) pathway cause cancer-predisposing Lynch Syndrome. We proposed that Lynch Syndrome-related germline mutations (LS-mutations) are associated with breast cancer (BC). In this study, we performed Targeted Next-Generation Sequencing of MMR pathway genes MLH1, MSH2, MSH6, EPCAM, and PMS2 in a cohort of 711 patients with hereditary BC, 60 patients with sporadic BC, and 492 healthy donors. Sixty-nine patients (9.7%) with hereditary BC harbored at least one germline mutation in the MMR pathway genes, of them 32 patients (4.5%) harbored mutations in MMR pathway genes which we define as pathogenic or likely pathogenic, and of them 26 patients (3.6%) did not have any pathogenic mutations in DDR pathway genes, compared to two mutations in MMR pathway genes (0.4%) detected in a group of 492 healthy donors [p = 0.00013, OR = 8.9 (CI 95% 2.2–78.4)]. Our study demonstrates that LS-mutations are present in patients with hereditary BC more frequently than in healthy donors, and that there is an association of hereditary BC and mutations c.1321G>A in MLH1, c.260C>G and c.2178G>C in MSH2, c.3217C>T in MSH6, c.1268C>G and c.86G>C in PMS2 genes. This finding provides a rationale for including pathogenic LS-mutations into genetic counseling tests for patients with hereditary BC.

Economic Burden of Depression and Associated Resource Use in Manitoba, Canada

OBJECTIVES

To characterize the health-care utilization and economic burden associated with depression in Manitoba, Canada.

METHODS

Patient-level data were retrieved from the Manitoba Centre for Health Policy administrative, clinical, and laboratory databases for the study period of January 1, 1996, through December 31, 2016. Patients were assigned to the depression cohort based on diagnoses recorded in hospitalizations and outpatient physician claims, as well as antidepressant prescription drug claims. A comparison cohort of nondepressed subjects, matched with replacement for age, gender, place of residence (urban vs. rural), and index date, was created. Demographics, comorbidities, intentional self-harm, mortality, health-care utilization, prescription drug utilization, and costs of health-care utilization and social services were compared between depressed patients and matched nondepressed patients, and incidence rate ratios and hazard ratios were reported.

RESULTS

There were 190,065 patients in the depression cohort and 378,177 patients in the nondepression cohort. Comorbidities were 43% more prevalent among depressed patients. Intentional self-harm, all-cause mortality, and suicide mortality were higher among patients with depression than the nondepression cohort. Health-care utilization-including hospitalizations, physician visits, physician-provided psychotherapy, and prescription drugs-was higher in the depression than the nondepression cohort. Mean health-care utilization costs were 3.5 times higher among depressed patients than nondepressed patients ($10,064 and $2,832, respectively). Similarly, mean social services costs were 3 times higher ($1,522 and $510, respectively). Overall, depression adds a total average cost of $8,244 (SD = $40,542) per person per year.

CONCLUSIONS

Depression contributes significantly to health burden and per patient costs in Manitoba, Canada. Extrapolation of the results to the entire Canadian health-care system projects an excess of $12 billion annually in health system spending.

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.

Effective Identification of Lynch Syndrome in Gastroenterology Practice

Purpose of review:

Identification of Lynch syndrome is important from an individual patient and public health standpoint. As paradigms for Lynch syndrome diagnosis have shifted in recent years, this review will discuss rationale and limitations for current strategies as well as provide an overview of future directions in the field.

Recent findings:

In recent years, the use of clinical criteria and risk scores for identification of Lynch syndrome have been augmented by universal testing of all newly diagnosed colorectal cancers with molecular methods to screen for mismatch repair deficiency with high sensitivity and specificity. Studies of implementation and outcomes of universal testing in clinical practice have demonstrated significant heterogeneity that results in suboptimal uptake and contributes to disparities in diagnosis. Emerging technologies, such as next-generation sequencing, hold significant promise as a screening strategy for Lynch syndrome.

Summary:

Universal testing for Lynch syndrome is being performed with increasing frequency, although real-world outcomes have demonstrated room for improvement. Future directions in Lynch syndrome diagnosis will involve optimization of universal testing workflow and application of new genetics technologies.

NCCN Guidelines Insights: Genetic/Familial High-Risk Assessment: Colorectal, Version 2.2019

Identifying individuals with hereditary syndromes allows for improved cancer surveillance, risk reduction, and optimized management. Establishing criteria for assessment allows for the identification of individuals who are carriers of pathogenic genetic variants. The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal provide recommendations for the assessment and management of patients with high-risk colorectal cancer syndromes. These NCCN Guidelines Insights focus on criteria for the evaluation of Lynch syndrome and considerations for use of multigene testing in the assessment of hereditary colorectal cancer syndromes.

Determination of Mismatch Repair Status in Human Cancer and Its Clinical Significance: Does One Size Fit All?

The clinical management of cancers has progressed rapidly into the immunopathology era, with the unprecedented histology-agnostic approval of pembrolizumab in mismatch repair (MMR) deficient tumors. Despite the significant recent achievements in the treatment of these patients, however, the identification of clinically relevant subclasses of cancers based on the MMR status remains a major challenge. Many investigations have assessed the role of different diagnostic tools, including immunohistochemistry, microsatellite instability, and tumor mutational burden in both prognostic and therapeutic settings, with heterogenous results. To date, there are no tumor-specific guidelines or companion diagnostic tests for MMR assessment, and this analysis is often performed with locally developed methods. In this review, we provide a comprehensive overview of the current state-of-knowledge of MMR alterations in syndromic and sporadic tumors and discuss the available armamentarium for MMR pathologic characterization, from morphology to high-throughput molecular tools.

Community Practice Implementation of a Self-administered Version of PREMM1,2,6 to Assess Risk for Lynch Syndrome

BACKGROUND & AIMS

Lynch syndrome is a genetic disorder that greatly increases risk for colorectal and other cancers, although it is underdiagnosed. Prediction of MLH1, MSH2, and MSH6 (PREMM_1,2,6) is a web-based tool that analyzes individuals' personal/family histories of cancer to quantify their likelihood of carrying a germline mutation associated with Lynch syndrome. We investigated the feasibility of systematic risk assessment for Lynch syndrome in a community gastroenterology practice using a patient-completed version of PREMM_1,2,6.

METHODS

PREMM_1,2,6 was adapted into a computer tablet version designed for self-administration by patients. Individuals presenting to a community gastroenterology office and endoscopy facility in California completed the PREMM_1,2,6 assessment before their visit (n = 3134). The total study duration (8 months) comprised a 2-month initiation period (May 1-June 30, 2013) and a 6-month study period (July 1-December 31, 2013). Genetic counseling and germline analysis for mutations in genes associated with Lynch syndrome (MLH1, MSH2, MSH6, PMS2, and EPCAM) were offered to individuals with PREMM_1,2,6 scores of 5% or higher. Patients and providers completed surveys to evaluate the feasibility and satisfaction with the process.

RESULTS

Of the 3134 individuals assessed by PREMM_1,2,6 during the 6-month study period, 177 individuals (5.6%) had scores of 5% or higher. Of these, 146 individuals underwent genetic testing, along with 28 additional participants recruited nonconsecutively during the initiation period. Mutations associated with Lynch syndrome were detected in 3 of the 146 individuals (2.1%) with PREMM_1,2,6 scores of 5% or higher who underwent germline testing, and 3 of the 28 patients (10.7%) recruited during study initiation with PREMM_1,2,6 scores of 5% or higher. Of the participants who underwent genetic analysis, 98.6% stated that they understood the information provided to them. All of the surveyed providers stated that they were satisfied with the incorporation of PREMM_1,2,6 into their clinical practice, and that they would continue using it to assess risk for Lynch syndrome.

CONCLUSIONS

A patient self-administered version of the PREMM_1,2,6 Lynch syndrome risk assessment model can be used systematically in community-based gastroenterology and endoscopy practices.

Poor performance of clinical prediction models: the harm of commonly applied methods

OBJECTIVE

To evaluate limitations of common statistical modeling approaches in deriving clinical prediction models and explore alternative strategies.

STUDY DESIGN AND SETTING

A previously published model predicted the likelihood of having a mutation in germline DNA mismatch repair genes at the time of diagnosis of colorectal cancer. This model was based on a cohort where 38 mutations were found among 870 participants, with validation in an independent cohort with 35 mutations. The modeling strategy included stepwise selection of predictors from a pool of over 37 candidate predictors and dichotomization of continuous predictors. We simulated this strategy in small subsets of a large contemporary cohort (2,051 mutations among 19,866 participants) and made comparisons to other modeling approaches. All models were evaluated according to bias and discriminative ability (concordance index, c) in independent data.

RESULTS

We found over 50% bias for five of six originally selected predictors, unstable model specification, and poor performance at validation (median c = 0.74). A small validation sample hampered stable assessment of performance. Model prespecification based on external knowledge and using continuous predictors led to better performance (c = 0.836 and c = 0.852 with 38 and 2,051 events respectively).

CONCLUSION

Prediction models perform poorly if based on small numbers of events and developed with common but suboptimal statistical approaches. Alternative modeling strategies to best exploit available predictive information need wider implementation, with collaborative research to increase sample sizes.

Genetic counseling and cascade genetic testing in Lynch syndrome

Lynch syndrome is the most common cause of inherited colorectal and endometrial cancers. Individuals with Lynch syndrome have a 10-80 % lifetime risk for colorectal cancer and a 15-60 % lifetime risk for endometrial cancer. Both cancers are preventable through chemoprevention, intensive cancer surveillance, and risk-reducing surgery options. Efforts to identify as many individuals with Lynch syndrome as possible will prevent cancers and save lives. This includes the traditional cancer genetic counseling model whereby individuals with and without cancer are evaluated for a possible Lynch syndrome diagnosis based on their personal and family history of colon polyps and cancers. It also includes universal tumor screening for Lynch syndrome whereby all individuals with colorectal or endometrial cancer are screened for tumor features of Lynch syndrome at the time of diagnosis. Those with tumors suspicious for Lynch syndrome are referred for cancer genetic counseling regardless of their family history of cancer. This two approaches must be maximized to attain high patient reach. Finally, and perhaps most importantly, cascade testing among the at-risk relatives of those diagnosed with Lynch syndrome is critically important to maximize the diagnosis of individuals with Lynch syndrome. In fact, the cost-effectiveness of universal tumor screening for Lynch syndrome relies entirely on counseling and testing as many at-risk individuals as possible since young unaffected individuals stand to benefit the most from an early diagnosis of Lynch syndrome. This approach must be optimized to achieve high family reach. It will take a concerted effort from patients, clinicians and public health officials to improve current approaches to the diagnosis of Lynch syndrome and the prevention and treatment of Lynch syndrome-associated cancer but these lessons can be applied to other conditions as the ultimate example of personalized medicine.

Development and Validation of the PREMM5 Model for Comprehensive Risk Assessment of Lynch Syndrome

Purpose Current Lynch syndrome (LS) prediction models quantify the risk to an individual of carrying a pathogenic germline mutation in three mismatch repair (MMR) genes: MLH1, MSH2, and MSH6. We developed a new prediction model, PREMM₅, that incorporates the genes PMS2 and EPCAM to provide comprehensive LS risk assessment. Patients and Methods PREMM₅ was developed to predict the likelihood of a mutation in any of the LS genes by using polytomous logistic regression analysis of clinical and germline data from 18,734 individuals who were tested for all five genes. Predictors of mutation status included sex, age at genetic testing, and proband and family cancer histories. Discrimination was evaluated by the area under the receiver operating characteristic curve (AUC), and clinical impact was determined by decision curve analysis; comparisons were made to the existing PREMM_1,2,6 model. External validation of PREMM₅ was performed in a clinic-based cohort of 1,058 patients with colorectal cancer. Results Pathogenic mutations were detected in 1,000 (5%) of 18,734 patients in the development cohort; mutations included MLH1 (n = 306), MSH2 (n = 354), MSH6 (n = 177), PMS2 (n = 141), and EPCAM (n = 22). PREMM₅ distinguished carriers from noncarriers with an AUC of 0.81 (95% CI, 0.79 to 0.82), and performance was similar in the validation cohort (AUC, 0.83; 95% CI, 0.75 to 0.92). Prediction was more difficult for PMS2 mutations (AUC, 0.64; 95% CI, 0.60 to 0.68) than for other genes. Performance characteristics of PREMM₅ exceeded those of PREMM_1,2,6. Decision curve analysis supported germline LS testing for PREMM₅ scores ≥ 2.5%. Conclusion PREMM₅ provides comprehensive risk estimation of all five LS genes and supports LS genetic testing for individuals with scores ≥ 2.5%. At this threshold, PREMM₅ provides performance that is superior to the existing PREMM_1,2,6 model in the identification of carriers of LS, including those with weaker phenotypes and individuals unaffected by cancer.

Prevalence and clinicopathologic/molecular characteristics of mismatch repair-deficient colorectal cancer in the under-50-year-old Japanese population

PURPOSE

To clarify the prevalence and clinicopathologic/molecular characteristics of mismatch repair (MMR)-deficient colorectal cancer in the young Japanese population.

METHODS

Immunohistochemical analyses for MMR proteins (MLH1, MSH2, MSH6, and PMS2) were performed in formalin-fixed paraffin-embedded sections prepared from the resected CRC specimens of 119 consecutive patients aged <50 years old, who underwent resection of the primary tumor at our institution between 1996 and 2015. Analyses for somatic BRAF V600E mutation, somatic hypermethylation of the MLH1 promoter, and germline MMR gene mutations were undertaken where indicated.

RESULTS

MMR protein loss was found in 10 patients (8.4%), 7 (5.9%) of whom were subsequently identified to have Lynch syndrome (LS). The remaining 3 patients were categorized as having sporadic MMR-deficient CRC (n = 2) or "possible LS (n = 1)". In multivariate logistic regression analysis, the presence of tumor-infiltrating lymphocytes (P < 0.01), right-sided location of the tumor (P = 0.01), and a history of LS-associated tumors in the first-degree relatives (P < 0.01) were identified as independent factors predictive of MMR-deficient CRC.

CONCLUSION

These results are of value in the clinical management of patients with the early onset CRC under circumstances where universal tumor screening approaches for LS are still not available, like in Japan.

Familial prostate cancer

Prostate cancer is the most commonly diagnosed cancer among men in the United States as well as most Western countries. A significant proportion of men report having a positive family history of prostate cancer in a first-degree relative (father, brother, son), which is important in that family history is one of the only established risk factors for the disease and plays a role in decision-making for prostate cancer screening. Familial aggregation of prostate cancer is considered a surrogate marker of genetic susceptibility to developing the disease, but shared environment cannot be excluded as an explanation for clustering of cases among family members. Prostate cancer is both a clinically and genetically heterogeneous disease with inherited factors predicted to account for 40%-50% of cases, comprised of both rare highly to moderately penetrant gene variants, as well as common genetic variants of low penetrance. Most notably, HOXB13 and BRCA2 mutations have been consistently shown to increase prostate cancer risk, and are more commonly observed among patients diagnosed with early-onset disease. A recurrent mutation in HOXB13 has been shown to predispose to hereditary prostate cancer (HPC), and BRCA2 mutations to hereditary breast and ovarian cancer (HBOC). Genome-wide association studies (GWAS) have also identified approximately 100 loci that associate with modest (odds ratios <2.0) increases in prostate cancer risk, only some of which have been replicated in subsequent studies. Despite these efforts, genetic testing in prostate cancer lags behind other common tumors like breast and colorectal cancer. To date, National Comprehensive Cancer Network (NCCN) guidelines have highly selective criteria for BRCA1/2 testing for men with prostate cancer based on personal history and/or specific family cancer history. Tumor sequencing is also leading to the identification of germline mutations in prostate cancer patients, informing the scope of inheritance. Advances in genetic testing for inherited and familial prostate cancer (FPC) are needed to inform personalized cancer risk screening and treatment approaches.

Universal Screening of Colorectal Cancers for Lynch Syndrome: Challenges and Opportunities

Lynch syndrome (LS) is the most common heritable colorectal cancer (CRC) syndrome, accounting for approximately 3 % of CRC cases in the USA each year. LS results from a genetic mutation in one of the four mismatch repair genes, and clinically LS is associated with CRC and other gastrointestinal and extra-gastrointestinal malignancies. In this review, we describe the various clinical criteria utilized for the identification of LS patients and the inherent flaws with these criteria. We discuss the concept of universal testing for LS in all cases of newly diagnosed CRC, along with the potential benefits and challenges of universal testing. Several studies have shown that universal tumor testing is cost-effective and identifies cases of LS that are missed using traditional clinical criteria, which may result in reduced cancer mortality for probands and their families. Yet the full benefits of universal tumor testing may be limited by the availability and patient acceptance of genetic testing, and by logistical obstacles affecting the implementation of universal testing programs. Lastly, we comment on developing technologies such as massively parallel next-generation sequencing, which permits simultaneous sequencing of multiple genes involved in LS and other inherited colon cancer syndromes.

Comparison of Prediction Models for Lynch Syndrome Among Individuals With Colorectal Cancer

BACKGROUND

Recent guidelines recommend the Lynch Syndrome prediction models MMRPredict, MMRPro, and PREMM1,2,6 for the identification of MMR gene mutation carriers. We compared the predictive performance and clinical usefulness of these prediction models to identify mutation carriers.

METHODS

Pedigree data from CRC patients in 11 North American, European, and Australian cohorts (6 clinic- and 5 population-based sites) were used to calculate predicted probabilities of pathogenic MLH1, MSH2, or MSH6 gene mutations by each model and gene-specific predictions by MMRPro and PREMM1,2,6. We examined discrimination with area under the receiver operating characteristic curve (AUC), calibration with observed to expected (O/E) ratio, and clinical usefulness using decision curve analysis to select patients for further evaluation. All statistical tests were two-sided.

RESULTS

Mutations were detected in 539 of 2304 (23%) individuals from the clinic-based cohorts (237 MLH1, 251 MSH2, 51 MSH6) and 150 of 3451 (4.4%) individuals from the population-based cohorts (47 MLH1, 71 MSH2, 32 MSH6). Discrimination was similar for clinic- and population-based cohorts: AUCs of 0.76 vs 0.77 for MMRPredict, 0.82 vs 0.85 for MMRPro, and 0.85 vs 0.88 for PREMM1,2,6. For clinic- and population-based cohorts, O/E deviated from 1 for MMRPredict (0.38 and 0.31, respectively) and MMRPro (0.62 and 0.36) but were more satisfactory for PREMM1,2,6 (1.0 and 0.70). MMRPro or PREMM1,2,6 predictions were clinically useful at thresholds of 5% or greater and in particular at greater than 15%.

CONCLUSIONS

MMRPro and PREMM1,2,6 can well be used to select CRC patients from genetics clinics or population-based settings for tumor and/or germline testing at a 5% or higher risk. If no MMR deficiency is detected and risk exceeds 15%, we suggest considering additional genetic etiologies for the cause of cancer in the family.

External Validation of a Referral Rule for Axial Spondyloarthritis in Primary Care Patients with Chronic Low Back Pain

Objectives

To validate and optimize a referral rule to identify primary care patients with chronic low back pain (CLBP) suspected for axial spondyloarthritis (axSpA).

Design

Cross-sectional study with data from 19 Dutch primary care practices for development and 38 for validation.

Participants

Primary care patients aged 18-45 years with CLBP existing more than three months and onset of back pain started before the age of 45 years.

Main Outcome

The number of axSpA patients according to the ASAS criteria.

Methods

The referral rule (CaFaSpA referral rule) was developed using 364 CLBP patients from 19 primary care practices and contains four easy to use variables; inflammatory back pain, good response to nonsteriodal anti-inflammatory drugs, family history of spondyloarthritis and a back pain duration longer than five years. This referral rule is positive when at least two variables are present. Validation of the CaFaSpA rule was accomplished in 579 primary care CLBP patients from 38 practices from other areas. Performance of the referral rule was assessed by c-statistic and calibration plot. To fit the final referral rule the development and validation datasets were pooled leading to a total study population of 943 primary care participants.

Results

The referral rule was validated in 579 patients (41% male, mean age 36 (sd7.0). The percentage of identified axSpA patients was 16% (n=95). External validation resulted in satisfactory calibration and reasonable discriminative ability (c-statistics 0.70 [95% CI, 0.64-0.75]). In the pooled dataset sensitivity and specificity of the referral rule were 75% and 58%.

Conclusions

The CaFaSpA referral rule for axSpA consists of four easy to use predictors for primary care physicians and has a good predictive value in this validation study. The referral rule has the potential to be a screening tool for primary care by identifying CLBP patients suspected for axSpA.

Genetics of endometrial cancer

Women who report a history of endometrial cancer in a first-degree relative are at increased risk of endometrial cancer, with a hazard ratio of 1.5 to 2.0. Only a minority of patients with familial endometrial cancer have a recognized cancer syndrome. Lynch syndrome is the most common genetic syndrome associated with endometrial cancer and a marked increased risk of colon cancer. Cowden syndrome is a rare condition resulting from a mutation in the tumor suppressor gene phosphatase and tensin homolog. The risk for endometrial cancer is about five times higher in women with Cowden syndrome than in the general population. Recently, a novel germline mutation in the POLD1 gene that encodes the catalytic subunit of DNA polymerase δ was described in several families with multiple cases of endometrial cancer. This mutation is also associated with colorectal cancer. The association between BRCA1 mutations and endometrial cancer has been investigated in several studies; it appears that the risk of endometrial cancer is restricted to women with a history of tamoxifen exposure. In recent years, research has focused on genetic polymorphisms that are associated with endometrial cancer risk. Although many polymorphisms have been identified, their clinical significance is unclear and they have not been adapted for clinical practice.

Development and analytical validation of a 25-gene next generation sequencing panel that includes the BRCA1 and BRCA2 genes to assess hereditary cancer risk

Background

Germline DNA mutations that increase the susceptibility of a patient to certain cancers have been identified in various genes, and patients can be screened for mutations in these genes to assess their level of risk for developing cancer. Traditional methods using Sanger sequencing focus on small groups of genes and therefore are unable to screen for numerous genes from several patients simultaneously. The goal of the present study was to validate a 25-gene panel to assess genetic risk for cancer in 8 different tissues using next generation sequencing (NGS) techniques.

Methods

Twenty-five genes associated with hereditary cancer syndromes were selected for development of a panel to screen for risk of these cancers using NGS. In an initial technical assessment, NGS results for BRCA1 and BRCA2 were compared with Sanger sequencing in 1864 anonymized DNA samples from patients who had undergone previous clinical testing. Next, the entire gene panel was validated using parallel NGS and Sanger sequencing in 100 anonymized DNA samples. Large rearrangement analysis was validated using NGS, microarray comparative genomic hybridization (CGH), and multiplex ligation-dependent probe amplification analyses (MLPA).

Results

NGS identified 15,877 sequence variants, while Sanger sequencing identified 15,878 in the BRCA1 and BRCA2 comparison study of the same regions. Based on these results, the NGS process was refined prior to the validation of the full gene panel. In the validation study, NGS and Sanger sequencing were 100% concordant for the 3,923 collective variants across all genes for an analytical sensitivity of the NGS assay of >99.92% (lower limit of 95% confidence interval). NGS, microarray CGH and MLPA correctly identified all expected positive and negative large rearrangement results for the 25-gene panel.

Conclusion

This study provides a thorough validation of the 25-gene NGS panel and indicates that this analysis tool can be used to collect clinically significant information related to risk of developing hereditary cancers.

Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD): explanation and elaboration

The TRIPOD (Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis) Statement includes a 22-item checklist, which aims to improve the reporting of studies developing, validating, or updating a prediction model, whether for diagnostic or prognostic purposes. The TRIPOD Statement aims to improve the transparency of the reporting of a prediction model study regardless of the study methods used. This explanation and elaboration document describes the rationale; clarifies the meaning of each item; and discusses why transparent reporting is important, with a view to assessing risk of bias and clinical usefulness of the prediction model. Each checklist item of the TRIPOD Statement is explained in detail and accompanied by published examples of good reporting. The document also provides a valuable reference of issues to consider when designing, conducting, and analyzing prediction model studies. To aid the editorial process and help peer reviewers and, ultimately, readers and systematic reviewers of prediction model studies, it is recommended that authors include a completed checklist in their submission. The TRIPOD checklist can also be downloaded from www.tripod-statement.org.

Role of microsatellite instability-low as a diagnostic biomarker of Lynch syndrome in colorectal cancer

Lynch syndrome is the most common Mendelian disorder predisposing persons to hereditary colorectal cancer. Carriers of MSH6 mutations constitute less than 10% of the total of cases with Lynch syndrome and present with a weaker clinical phenotype, including low levels of microsatellite instability (MSI-L) in colorectal tumors. The frequency of MSH6 mutation carriers among patients presenting with MSI-L colorectal cancer has yet to be determined, as has the appropriate genetic workup in this context. We have reviewed here the clinicopathologic characteristics, immunohistochemistry, and genetic testing results for 71 patients at a single institution diagnosed with MSI-L colorectal cancers. Of 71 patients with MSI-L tumors, 21 underwent genetic testing for MSH6 mutations, three of whom presented with loss of staining of MSH6 and only one of whom carried a pathogenic germline MSH6 mutation in exon 4 (c.2677_2678delCT; p.Leu893Alafs*6). This latter patient had a significant family history of cancer and had a rectal primary tumor that showed instability only in mononucleotide markers. In this cohort of MSI-L patients, we detected no notable clinicopathologic or molecular characteristic that would help to distinguish a group most likely to harbor germline MSH6 mutations. Therefore, we conclude that the prevalence of MSH6 mutations among patients with MSI-L tumors is very low. Microsatellite instability analysis combined with immunohistochemistry of mismatch repair proteins adequately detects potential MSH6 mutation carriers among MSI-L colorectal cancers.

Germline rearrangements in families with strong family history of glioma and malignant melanoma, colon, and breast cancer

BACKGROUND

Although familial susceptibility to glioma is known, the genetic basis for this susceptibility remains unidentified in the majority of glioma-specific families. An alternative approach to identifying such genes is to examine cancer pedigrees, which include glioma as one of several cancer phenotypes, to determine whether common chromosomal modifications might account for the familial aggregation of glioma and other cancers.

METHODS

Germline rearrangements in 146 glioma families (from the Gliogene Consortium; http://www.gliogene.org/) were examined using multiplex ligation-dependent probe amplification. These families all had at least 2 verified glioma cases and a third reported or verified glioma case in the same family or 2 glioma cases in the family with at least one family member affected with melanoma, colon, or breast cancer.The genomic areas covering TP53, CDKN2A, MLH1, and MSH2 were selected because these genes have been previously reported to be associated with cancer pedigrees known to include glioma.

RESULTS

We detected a single structural rearrangement, a deletion of exons 1-6 in MSH2, in the proband of one family with 3 cases with glioma and one relative with colon cancer.

CONCLUSIONS

Large deletions and duplications are rare events in familial glioma cases, even in families with a strong family history of cancers that may be involved in known cancer syndromes.

Prediction models in Lynch syndrome

Prediction models for the identification of Lynch syndrome have been developed to quantify an individual's risk of carrying a mismatch repair gene mutation and help clinicians decide for whom further risk assessment and genetic testing is necessary. There are diverse clinical settings in which a healthcare provider has the opportunity to assess an individual for Lynch syndrome. Prediction models offer a potentially feasible and useful strategy to systematically identify at-risk individuals, whether they are affected with colorectal cancer or not, and to help with management of the implications of molecular and germline test results. Given the complexity of diagnostic information currently available to clinicians involved in identifying and caring for patients with Lynch syndrome, prediction models provide a useful and complementary aid in medical decision-making. Systematic implementation of prediction models estimates should be considered in routine clinical care and at various stages of cancer risk assessment and prevention. In this manuscript, we review the main prediction models developed for Lynch syndrome, focus on their specific features and performance assessed in several validation studies, compare the models with other clinical and molecular strategies for the diagnosis of Lynch syndrome, and discuss their potential uses in clinical practice.

Criteria and prediction models for mismatch repair gene mutations: a review

One of the strongest predictors of colorectal cancer risk is carrying a germline mutation in a DNA mismatch repair (MMR) gene. Once identified, mutation carriers can be recommended for intensive screening that will substantially reduce their high colorectal cancer risk. Conversely, the relatives of carriers identified as non-carriers can be relieved of the burden of intensive screening. Criteria and prediction models that identify likely mutation carriers are needed for cost-effective, targeted, germline testing for MMR gene mutation. We reviewed 12 criteria/guidelines and 8 prediction models (Leiden, Amsterdam-plus, Amsterdam-alternative, MMRpro, PREMM1,2,6, MMRpredict, Associazione Italiana per lo studio della Familiarità ed Ereditarietà dei tumori Gastrointestinali (AIFEG) and the Myriad Genetics Prevalence table) for identifying mutation carriers. While criteria are only used to identify individuals with colorectal cancer (yes/no for screening followed by germline testing), all prediction models except MMRpredict and Myriad tables can predict the probability of carrying mutations for individuals with or without colorectal cancer. We conducted a meta-analysis of the discrimination performance of 17 studies that validated the prediction models. The pooled estimate for the area under curve was 0.80 (95% CI 0.72 to 0.88) for MMRpro, 0.81 (95% CI 0.73 to 0.88) for MMRpredict, 0.84 (95% CI 0.81 to 0.88) for PREMM, and 0.85 (95% CI 0.78 to 0.91) for Leiden model. Given the high degree of overlap in the CIs, we cannot state that one model has a higher discrimination than any of the others. Overall, the existing statistical models have been shown to be sensitive and specific (at a 5% cut-off) in predicting MMR gene mutation carriers. Future models may need to: provide prediction of PMS2 mutations, take into account a wider range of Lynch syndrome-associated cancers when assessing family history, and be applicable to all people irrespective of any cancer diagnosis.

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.

Bethesda criteria for microsatellite instability testing: impact on the detection of new cases of Lynch syndrome

In 1997 Bethesda Guidelines (BG) were established and in 2004 those criteria were revised (RBG), with the main goal of selecting colorectal cancers (CRC) that should be subjected to microsatellite instability (MSI) testing. High microsatellite instability (MSI-H) is an intermediate marker for mutational analysis of the mismatch repair (MMR) genes involved in the genesis of Lynch Syndrome (LS). We aimed to evaluate and compare BG/RBG in the detection of MSI-H and subsequent identification of pathogenic MMR genes mutations. We included 174 patients with CRC and indication for MSI analysis according to BG or RBG. MSI testing was performed with the Bethesda markers and mutational analysis of MLH1, MSH2 and MSH6 genes undertaken with DGGE, MLPA and direct sequencing. One hundred fourteen of 174 patients (65.5 %) fulfilled BG and all of them RBG. With the BG, MSI-H was detected in 37/114 (32.5 %) CRCs and mutational analysis was positive in 14/37 (37.8 %) patients. The RBG led to detection of MSI-H in 49/174 (28.2 %) of the CRCs, having the mutational analysis been positive in 16/49 (32.7 %) patients. We could identify 14/114 (12.3 %) new cases of LS, through BG and 16/174 (9.2 %) via RBG. BG presented a similar overall percentage for the detection of MSI-H and mutations when compared with RBG. RBG implicated the analysis of more patients, though they gave rise to detection of two additional LS cases. This difference has a significant impact on the establishment of preventive measures, mainly for CRC, in all the mutation-carriers belonging to these families.

Lynch syndrome related endometrial cancer: clinical significance beyond the endometrium

Lynch syndrome (LS), an autosomal dominant inherited cancer susceptibility syndrome, also known as hereditary non-polyposis colon cancer (HNPCC), is caused by a germline mutation in one of several DNA mismatch repair (MMR) genes. LS is the most common presentation of hereditary colorectal cancer (CRC), accounting for about 2–5% of all CRC cases. More recently, it is found that a similar number of endometrial cancers is also due to one of the MMR gene mutations. There has been significant progress in LS-related CRC in terms of molecular pathogenesis, risks, genetic basis, and cancer prevention. In contrast, the advance about LS-related endometrial cancer (EC) is very much limited. In this commentary, we summarize the main clinicopathologic features of LS-related EC and propose universal screening for LS in individuals with endometrial cancer.

Prevalence of pathological germline mutations of hMLH1 and hMSH2 genes in colorectal cancer

The prevalence of pathological germline mutations in colorectal cancer has been widely studied, as germline mutations in the DNA mismatch repair genes hMLH1 and hMSH2 confer a high risk of colorectal cancer. However, because the sample size and population of previous studies are very different from each other, the conclusions still remain controversial. In this paper, Databases such as PubMed were applied to search for related papers. The data were imported into Comprehensive Meta-Analysis V2, which was used to estimate the weighted prevalence of hMLH1 and hMSH2 pathological mutations and compare the differences of prevalence among different family histories, ethnicities and related factors. This study collected and utilized data from 102 papers. In the Amsterdam-criteria positive group, the prevalence of pathological germline mutations of the hMLH1 and hMSH2 genes was 28.55% (95%CI 26.04%–31.19%) and 19.41% (95%CI 15.88%–23.51%), respectively, and the prevalence of germline mutations in hMLH1/hMSH2 was 15.44%/10.02%, 20.43%/13.26% and 15.43%/11.70% in Asian, American multiethnic and European/Australian populations, respectively. Substitution mutations accounted for the largest proportion of germline mutations (hMLH1: 52.34%, hMSH2: 43.25%). The total prevalence of mutations of hMLH1 and hMSH2 in Amsterdam-criteria positive, Amsterdam-criteria negative and sporadic colorectal cancers was around 45%, 25% and 15%, respectively, and there were no obvious differences in the prevalence of germline mutations among different ethnicities.

Genetic testing by cancer site: uterus

This review article discusses hereditary cancer predisposition syndromes with uterine manifestations. Lynch syndrome accounts for 2% to 3% of endometrial cancers. The identification of endometrial cancer patients at risk for Lynch syndrome is discussed, as are the characteristics of Lynch syndrome-associated endometrial cancer and the screening and prevention options for women at risk for Lynch syndrome-associated endometrial cancer. Endometrial cancer associated with PTEN hamartoma tumor syndrome (also known as Cowden syndrome) is also discussed. HLRCC (hereditary leiomyomatosis and renal cell carcinoma), which has an associated high risk of symptomatic uterine leiomyomas, is reviewed.

Cancer Stem Cells in Colorectal Cancer: Genetic and Epigenetic Changes

Colorectal cancer (CRC), an age-related disease, is the third most common cancer in the world. Although sporadic CRC, that affects 80-85% of CRC patients, is a multi-step process initiated by APC gene mutation, it is becoming increasingly evident that a small sub-population of cells termed cancer stem/stem-like cells (CSCs/CSLCs) plays critical roles in the progression of this malignancy specially the recurrence and drug resistance. The current review will summarize genetic and epigenetic changes observed at different stages in the progression of sporadic CRC. In addition, roles of miRNAs that control gene expression and CSCs/CSLCs in regulating proliferation, differentiation, and survival of the colon cancer cells will be summarized.

Identification of Lynch syndrome among patients with colorectal cancer

CONTEXT

Lynch syndrome is the most common form of hereditary colorectal cancer (CRC) and is caused by germline mutations in DNA mismatch repair (MMR) genes. Identification of gene carriers currently relies on germline analysis in patients with MMR-deficient tumors, but criteria to select individuals in whom tumor MMR testing should be performed are unclear.

OBJECTIVE

To establish a highly sensitive and efficient strategy for the identification of MMR gene mutation carriers among CRC probands.

DESIGN, SETTING, AND PATIENTS

Pooled-data analysis of 4 large cohorts of newly diagnosed CRC probands recruited between 1994 and 2010 (n = 10,206) from the Colon Cancer Family Registry, the EPICOLON project, the Ohio State University, and the University of Helsinki examining personal, tumor-related, and family characteristics, as well as microsatellite instability, tumor MMR immunostaining, and germline MMR mutational status data.

MAIN OUTCOME

Performance characteristics of selected strategies (Bethesda guidelines, Jerusalem recommendations, and those derived from a bivariate/multivariate analysis of variables associated with Lynch syndrome) were compared with tumor MMR testing of all CRC patients (universal screening).

RESULTS

Of 10,206 informative, unrelated CRC probands, 312 (3.1%) were MMR gene mutation carriers. In the population-based cohorts (n = 3671 probands), the universal screening approach (sensitivity, 100%; 95% CI, 99.3%-100%; specificity, 93.0%; 95% CI, 92.0%-93.7%; diagnostic yield, 2.2%; 95% CI, 1.7%-2.7%) was superior to the use of Bethesda guidelines (sensitivity, 87.8%; 95% CI, 78.9%-93.2%; specificity, 97.5%; 95% CI, 96.9%-98.0%; diagnostic yield, 2.0%; 95% CI, 1.5%-2.4%; P < .001), Jerusalem recommendations (sensitivity, 85.4%; 95% CI, 77.1%-93.6%; specificity, 96.7%; 95% CI, 96.0%-97.2%; diagnostic yield, 1.9%; 95% CI, 1.4%-2.3%; P < .001), and a selective strategy based on tumor MMR testing of cases with CRC diagnosed at age 70 years or younger and in older patients fulfilling the Bethesda guidelines (sensitivity, 95.1%; 95% CI, 89.8%-99.0%; specificity, 95.5%; 95% CI, 94.7%-96.1%; diagnostic yield, 2.1%; 95% CI, 1.6%-2.6%; P < .001). This selective strategy missed 4.9% of Lynch syndrome cases but resulted in 34.8% fewer cases requiring tumor MMR testing and 28.6% fewer cases undergoing germline mutational analysis than the universal approach.

CONCLUSION

Universal tumor MMR testing among CRC probands had a greater sensitivity for the identification of Lynch syndrome compared with multiple alternative strategies, although the increase in the diagnostic yield was modest.

Lynch syndrome diagnostics: decision-making process for germ-line testing

Cancer risks and medical management of Lynch syndrome (LS) differ from other hereditary or familial clustering of colorectal cancer. Differential diagnosis has improved as a result of the growing clinical and molecular knowledge about LS. Appropriate application of these advances in several scenarios constitutes a decision-making process to further decide germ-line testing with accuracy and efficiency. However, an only molecular-screening algorithm, with a limited number of steps and choices, may be difficult to devise. How, when, where and at what expense to use the different diagnostic tools remain dynamic and changeable under different circumstances. From a clinical point of view, it is advisable to discuss conflicting aspects to guide LS diagnosis.