MSH2 mutation carriers are at higher risk of cancer than MLH1 mutation carriers: a study of hereditary nonpolyposis colorectal cancer families

A case report: Gliosarcoma associated with a germline heterozygous mutation in MSH2

Gliosarcoma is a rare subtype of glioblastoma (GBM) with a shorter medical history and a worse prognosis compared to other Grade 4 gliomas. Most gliosarcomas are sporadic, but it is undeniable that a small percentage are linked to germline mutations and several inherited cancer susceptibility syndromes, including Lynch Syndrome (LS). The authors present a case of a primary mismatch repair-deficient gliosarcoma in LS. A 54-year-old Chinese male patient was admitted to the hospital with a history of facial asymmetry for over 1 month and right temporo-occipital pain for 5 days. Head MRI revealed a complex mass lesion in the right frontoparietal region, consisting of cystic and solid components. The patient's history of colon malignancy and family history of rectal carcinoma were noteworthy. Postoperative pathology indicated the presence of gliosarcoma with high-frequency microsatellite instability (MSI-H) and mismatch repair deficiency (MMRD). Further genetic testing results confirmed a germline heterozygous mutation in MSH2, which is considered the gold standard for diagnosing LS. This case report enriches the existing literature on germline MSH2 mutations and gliosarcomas. It highlights the importance for neurosurgeons to consider possible hereditary disorders when treating patients with a history of concurrent tumors outside the nervous system. Genetic testing is crucial for further identification of such disorders.

Lynch Syndrome: From Multidisciplinary Management to Precision Prevention

BACKGROUND AND AIMS

Lynch syndrome (LS) is currently one of the most prevalent hereditary cancer conditions, accounting for 3% of all colorectal cancers and for up to 15% of those with DNA mismatch repair (MMR) deficiency, and it was one of the first historically identified. The understanding of the molecular carcinogenesis of LS tumors has progressed significantly in recent years. We aim to review the most recent advances in LS research and explore genotype-based approaches in surveillance, personalized cancer prevention, and treatment strategies.

METHODS

PubMed was searched to identify relevant studies, conducted up to December 2023, investigating molecular carcinogenesis in LS, surveillance strategies, cancer prevention, and treatment in LS tumors.

RESULTS

Multigene panel sequencing is becoming the benchmark in the diagnosis of LS, allowing for the detection of a pathogenic constitutional variant in one of the MMR genes. Emerging data from randomized controlled trials suggest possible preventive roles of resistant starch and/or aspirin in LS. Vaccination with immunogenic frameshift peptides appears to be a promising approach for both the treatment and prevention of LS-associated cancers, as evidenced by pre-clinical and preliminary phase 1/2a studies.

CONCLUSIONS

Although robust diagnostic algorithms, including prompt testing of tumor tissue for MMR defects and referral for genetic counselling, currently exist for suspected LS in CRC patients, the indications for LS screening in cancer-free individuals still need to be refined and standardized. Investigation into additional genetic and non-genetic factors that may explain residual rates of interval cancers, even in properly screened populations, would allow for more tailored preventive strategies.

Characteristics of glioblastomas and immune microenvironment in a Chinese family with Lynch syndrome and concurrent porokeratosis

Background

Lynch syndrome (LS)-associated glioblastoma (GBM) is rare in clinical practice, and simultaneous occurrence with cutaneous porokeratosis is even rarer. In this study, we analyzed the clinicopathological and genetic characteristics of LS-associated GBMs and concurrent porokeratosis, as well as evaluated the tumor immune microenvironment (TIME) of LS-associated GBMs.

Methods

Immunohistochemical staining was used to confirm the histopathological diagnosis, assess MMR and PD-1/PD-L1 status, and identify immune cell subsets. FISH was used to detect amplification of EGFR and PDGFRA, and deletion of 1p/19q and CDKN2A. Targeted NGS assay analyzed somatic variants, MSI, and TMB status, while whole-exome sequencing and Sanger sequencing were carried out to analyze the germline mutations.

Results

In the LS family, three members (I:1, II:1 and II:4) were affected by GBM. GBMs with loss of MSH2 and MSH6 expression displayed giant and multinucleated bizarre cells, along with mutations in ARID1A, TP53, ATM, and NF1 genes. All GBMs had TMB-H but not MSI-H. CD8+ T cells and CD163+ macrophages were abundant in each GBM tissue. The primary and recurrent GBMs of II:1 showed mesenchymal characteristics with high PD-L1 expression. The family members harbored a novel heterozygous germline mutation in MSH2 and FDPS genes, confirming the diagnosis of LS and disseminated superficial actinic porokeratosis.

Conclusion

LS-associated GBM exhibits heterogeneity in clinicopathologic and molecular genetic features, as well as a suppressive TIME. The presence of MMR deficiency and TMB-H may serve as predictive factors for the response to immune checkpoint inhibitor therapy in GBMs. The identification of LS-associated GBM can provide significant benefits to both patients and their family members, including accurate diagnosis, genetic counseling, and appropriate screening or surveillance protocols. Our study serves as a reminder to clinicians and pathologists to consider the possibility of concurrent genetic syndromes in individuals or families.

Penetrance of Gastric Adenocarcinoma Susceptibility Genes: A Systematic Review

BACKGROUND

Gastric adenocarcinoma (GAC) is the fifth most common cancer in the world, and the presence of germline pathogenic variants has been linked with approximately 5% of gastric cancer diagnoses. Multiple GAC susceptibility genes have been identified, but information regarding the risk associated with pathogenic variants in these genes remains obscure. We conducted a systematic review of existing studies reporting the penetrance of GAC susceptibility genes.

METHODS

A structured search query was devised to identify GAC-related papers indexed in MEDLINE/PubMed. A semi-automated natural language processing algorithm was applied to identify penetrance papers for inclusion. Original studies reporting the penetrance of GAC were included and the full-text articles were independently reviewed. Summary statistics, effect estimates, and precision parameters from these studies were compiled into a table using a predetermined format to ensure consistency.

RESULTS

Forty-five studies were identified reporting the penetrance of GAC among patients harboring mutations in 13 different genes: APC, ATM, BRCA1, BRCA2, CDH1, CHEK2, MLH1, MSH2, MSH6, PMS2, MUTYH-Monoallelic, NBN, and STK11.

CONCLUSION

Our systematic review highlights the importance of testing for germline pathogenic variants in patients before the development of GAC. Management of patients who harbor a pathogenic mutation is multifactorial, and clinicians should consider cancer risk for each applicable gene-cancer association throughout the screening and management process. The scarcity of studies we found investigating the risk of GAC among patients with pathogenic variants in GAC susceptibility genes highlights the need for more investigations that focus on producing robust risk estimates for gene-cancer associations.

Lynch Syndrome and Gynecologic Tumors: Incidence, Prophylaxis, and Management of Patients with Cancer

This review provides a comprehensive update on recent evidence regarding gynecologic tumors associated with Lynch Syndrome (LS). Endometrial cancer (EC) and ovarian cancer (OC) are the first and second most common gynecologic malignancies in developed countries, respectively, and LS is estimated to be the hereditary cause in 3% of both EC and OC. Despite the increasing evidence on LS-related tumors, few studies have analyzed the outcomes of LS-related EC and OC stratified by mutational variant. This review aims to provide a comprehensive overview of the literature and comparison between updated international guidelines, to help outline a shared pathway for the diagnosis, prevention, and management of LS. Through the widespread adoption of the immunohistochemistry-based Universal Screening, LS diagnosis and identification of mutational variants could be standardized and recognized by international guidelines as a feasible, reproducible, and cost-effective method. Furthermore, the development of a better understanding of LS and its mutational variants will support our ability to better tailor EC and OC management in terms of prophylactic surgery and systemic treatment in the light of the promising results shown by immunotherapy.

A Rare MSH2 Variant as a Candidate Marker for Lynch Syndrome II Screening in Tunisia: A Case of Diffuse Gastric Carcinoma

Several syndromic forms of digestive cancers are known to predispose to early-onset gastric tumors such as Hereditary Diffuse Gastric Cancer (HDGC) and Lynch Syndrome (LS). LSII is an extracolonic cancer syndrome characterized by a tumor spectrum including gastric cancer (GC). In the current work, our main aim was to identify the mutational spectrum underlying the genetic predisposition to diffuse gastric tumors occurring in a Tunisian family suspected of both HDGC and LS II syndromes. We selected the index case “JI-021”, which was a woman diagnosed with a Diffuse Gastric Carcinoma and fulfilling the international guidelines for both HDGC and LSII syndromes. For DNA repair, a custom panel targeting 87 candidate genes recovering the four DNA repair pathways was used. Structural bioinformatics analysis was conducted to predict the effect of the revealed variants on the functional properties of the proteins. DNA repair genes panel screening identified two variants: a rare MSH2 c.728G>A classified as a variant with uncertain significance (VUS) and a novel FANCD2 variant c.1879G>T. The structural prediction model of the MSH2 variant and electrostatic potential calculation showed for the first time that MSH2 c.728G>A is likely pathogenic and is involved in the MSH2-MLH1 complex stability. It appears to affect the MSH2-MLH1 complex as well as DNA-complex stability. The c.1879G>T FANCD2 variant was predicted to destabilize the protein structure. Our results showed that the MSH2 p.R243Q variant is likely pathogenic and is involved in the MSH2-MLH1 complex stability, and molecular modeling analysis highlights a putative impact on the binding with MLH1 by disrupting the electrostatic potential, suggesting the revision of its status from VUS to likely pathogenic. This variant seems to be a shared variant in the Mediterranean region. These findings emphasize the importance of testing DNA repair genes for patients diagnosed with diffuse GC with suspicion of LSII and colorectal cancer allowing better clinical surveillance for more personalized medicine.

Risk of Metachronous Colorectal Cancer in Lynch Syndrome: Who Needs an Extended Resection?

Lynch syndrome (LS) is the most common genetic condition associated with early-onset colorectal cancer. It is inherited in an autosomal dominant fashion. The increased cancer risk is due to a germline mutation in one of the mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) or the EPCAM gene. This leads to a deficient DNA mismatch repair mechanism, resulting in the accumulation of nucleotide changes and microsatellite instability, providing phenotypical evidence that MMR is not functioning normally. LS is associated with a high risk of early-onset colorectal cancer and recurrence. Thus, when undergoing surgery for primary colorectal cancer, extended resection should be discussed with the patient. This review provides an overview of current surgical risk-reducing strategies in LS-associated colorectal cancer. Surgical treatment for LS carriers with colorectal cancer needs to be highly individualized, based on patient and disease characteristics. Strategies are presented to guide decision making in pathologic MMR gene mutation carriers undergoing surgery for colorectal cancer.

Molecular pathogenesis and emerging targets of gastric adenocarcinoma

Gastric adenocarcinoma (GC) is a devastating disease and is the third leading cause of cancer deaths worldwide. This heterogeneous disease has several different classification systems that consider histological appearance and genomic alterations. Understanding the etiology of GC, including infection, hereditary conditions, and environmental factors, is of particular importance and is discussed in this review. To improve survival in GC, we also must improve our therapeutic strategies. Here, we discuss new targets that warrant further exploration.

Environmental and genetic risk factors for gastric cancer

Gastric cancer is a heterogeneous and prevalent disease. The traditional environmental exposures associated with an elevated risk of gastric cancer are less prevalent in the United States today. Genetic risks and risks associated with inflammation remain. Most cases are sporadic and familial clustering is observed in about 10% of the cases. Hereditary gastric cancer accounts for a very low percentage of cases. Here we review the genetic and environmental risk factors associated with the disease.

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

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

Cost-Effectiveness of Colorectal Cancer Genetic Testing

Colorectal cancer (CRC) remains the second leading cause of cancer-related deaths worldwide. Approximately 3–5% of CRCs are associated with hereditary cancer syndromes. Individuals who harbor germline mutations are at an increased risk of developing early onset CRC, as well as extracolonic tumors. Genetic testing can identify genes that cause these syndromes. Early detection could facilitate the initiation of targeted prevention strategies and surveillance for CRC patients and their families. The aim of this study was to determine the cost-effectiveness of CRC genetic testing. We utilized a cross-sectional design to determine the cost-effectiveness of CRC genetic testing as compared to the usual screening method (iFOBT) from the provider’s perspective. Data on costs and health-related quality of life (HRQoL) of 200 CRC patients from three specialist general hospitals were collected. A mixed-methods approach of activity-based costing, top-down costing, and extracted information from a clinical pathway was used to estimate provider costs. Patients and family members’ HRQoL were measured using the EQ-5D-5L questionnaire. Data from the Malaysian Study on Cancer Survival (MySCan) were used to calculate patient survival. Cost-effectiveness was measured as cost per life-year (LY) and cost per quality-adjusted life-year (QALY). The provider cost for CRC genetic testing was high as compared to that for the current screening method. The current practice for screening is cost-saving as compared to genetic testing. Using a 10-year survival analysis, the estimated number of LYs gained for CRC patients through genetic testing was 0.92 years, and the number of QALYs gained was 1.53 years. The cost per LY gained and cost per QALY gained were calculated. The incremental cost-effectiveness ratio (ICER) showed that genetic testing dominates iFOBT testing. CRC genetic testing is cost-effective and could be considered as routine CRC screening for clinical practice.

When to Consider Lynch Syndrome in Non-Colon and Non-Endometrial Malignancies

Lynch syndrome (LS) is a common genetic syndrome characterized by pathogenic mutations of DNA mismatch repair genes resulting in a hereditary predisposition to cancer. While typically associated with colonic and endometrial cancer, LS additionally influences the development of many other malignancies. The Amsterdam II and Revised Bethesda Guidelines are the established clinical criteria for diagnosing LS. These guidelines are based on the most general characteristics of LS and do not address specific characteristics of the less commonly LS-associated malignancies. For individuals that present initially with a non-colon and non-endometrial malignancy, recommendations and guidelines on when to consider screening for LS are limited. Therefore, it is essential that clinicians are familiar with distinct LS-associated patient- and tumor-specific characteristics, especially of the less common LS-associated cancers, so that LS's diagnosis is not missed. In this review article, we focus on extra-colonic and extra-endometrial LS-associated cancers, paying particular attention to any established or currently investigated cancer features that help raise suspicion for LS and potentially lead to its earlier diagnosis. This review will also discuss current guidelines specific to each LS-associated malignancy.

Precision medicine for hereditary tumors in gynecologic malignancies

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

Lynch Syndrome: Its Impact on Urothelial Carcinoma

Lynch syndrome, known as hereditary nonpolyposis colorectal cancer (HNPCC), is an autosomal-dominant familial cancer syndrome with an increased risk for urothelial cancer (UC). Mismatch repair (MMR) deficiency, due to pathogenic variants in MLH1, MSH2, MSH6, and PMS2, and microsatellite instability, are known for development of Lynch syndrome (LS) associated carcinogenesis. UC is the third most common cancer type in LS-associated tumors. The diversity of germline variants in the affected MMR genes and their following subsequent function loss might be responsible for the variation in cancer risk, suggesting an increased risk of developing UC in MSH2 mutation carriers. In this review, we will focus on LS-associated UC of the upper urinary tract (UUT) and bladder, their germline profiles, and outcomes compared to sporadic UC, the impact of genetic testing, as well as urological follow-up strategies in LS. In addition, we present a case of metastatic LS-associated UC of the UUT and bladder, achieving complete response during checkpoint inhibition since more than 2 years.

Associations Between Mutations in MSH6 and PMS2 and Risk of Surveillance-detected Colorectal Cancer

BACKGROUND & AIMS

Lynch syndrome is the most common inherited cause of colorectal cancer (CRC). Contemporary and mutation-specific estimates of CRC-risk in patients undergoing colonoscopy would optimize surveillance strategies. We performed a prospective national cohort study, using data from New Zealand, to assess overall and mutation-specific risk of CRC in patients with Lynch syndrome undergoing surveillance.

METHODS

We performed a prospective study of 381 persons with Lynch syndrome in New Zealand (98 with Lynch-syndrome associated variants in MLH1, 159 in MSH2, 103 in MSH6, and 21 in PMS2). Participants were offered annual colonoscopy starting at age 25 y, and those who underwent 2 or more colonoscopies before December 31, 2017 were included in the final analysis. Patients with previous colonic resection, history of CRC or diagnosis of CRC at index colonoscopy were excluded.

RESULTS

Study participants underwent 2061 colonoscopies during 2296 person-y; the median observation-period was 4.43 y and mean-age at enrollment was 43 y. Eighteen patients developed CRC (8 with variants in MLH1, 8 in MSH2, and 2 in MSH6) after a median follow-up period of 6.5 y (range 1-16 y). Eighty-three percent of patients had a surveillance colonoscopy in preceding 24 months before diagnosis of CRC; 94% were diagnosed with stage 0-II CRC and there was no CRC-related mortality. The overall-risk of developing CRC in the 5 y after first surveillance colonoscopy was 2.49% (95% CI, 1.18-5.23); cumulative risks for CRC in patients with Lynch syndrome-associated variants in MLH1, MSH2, or MSH6 by age 70 y were 17.7%, 17.8%, and 8.5%, respectively. Age-adjusted CRC-risk in patients with variants in MSH6 was lower than in MLH1 (hazard ratio, 0.2; 95% CI, 0.04-0.94; P = .02). Of patients with CRC, 33% had an adenomatous polyp resected from same segment in which a colorectal tumor later developed.

CONCLUSIONS

The risk of CRC in patients with Lynch syndrome-associated mutations in MSH6 or PMS2 was significantly lower than in patients with mutations in MLH1. Incomplete adenomatous polyp resection might be responsible for one third of surveillance-detected CRCs.

Value of upper gastrointestinal endoscopy for gastric cancer surveillance in patients with Lynch syndrome

In our study, we evaluated the effectiveness of upper gastrointestinal (GI) endoscopy as an instrument for early gastric cancer (GC) detection in Lynch syndrome (LS) patients by analyzing data from the registry of the German Consortium for Familial Intestinal Cancer. In a prospective, multicenter cohort study, 1128 out of 2009 registered individuals with confirmed LS underwent 5176 upper GI endoscopies. Compliance was good since 77.6% of upper GI endoscopies were completed within the recommended interval of 1 to 3 years. Forty-nine GC events were observed in 47 patients. MLH1 (n = 21) and MSH2 (n = 24) mutations were the most prevalent. GCs in patients undergoing regular surveillance were diagnosed significantly more often in an early-stage disease (UICC I) than GCs detected through symptoms (83% vs 25%; P = .0231). Thirty-two (68%) patients had a negative family history of GC. The median age at diagnosis was 51 years (range 28-66). Of all GC patients, 13 were diagnosed at an age younger than 45. Our study supports the recommendation of regular upper GI endoscopy surveillance for LS patients beginning no later than at the age of 30.

Penetrance of Colorectal Cancer Among Mismatch Repair Gene Mutation Carriers: A Meta-Analysis

Background

Lynch syndrome, the most common colorectal cancer (CRC) syndrome, is caused by germline mismatch repair (MMR) genes. Precise estimates of age-specific risks are crucial for sound counseling of individuals managing a genetic predisposition to cancer, but published risk estimates vary. The objective of this work is to provide gene-, sex-, and age-specific risk estimates of CRC for MMR mutation carriers that comprehensively reflect the best available data.

Methods

We conducted a meta-analysis to combine risk information from multiple studies on Lynch syndrome-associated CRC. We used a likelihood-based approach to integrate reported measures of CRC risk and deconvolved aggregated information to estimate gene- and sex-specific risk.

Results

Our comprehensive search identified 10 studies (8 on MLH1, 9 on MSH2, and 3 on MSH6). We estimated the cumulative risk of CRC by age and sex in heterozygous mutation carriers. At age 70 years, for male and female carriers, respectively, risks for MLH1 were 43.9% (95% confidence interval [CI] = 39.6% to 46.6%) and 37.3% (95% CI = 32.2% to 40.2%), for MSH2 were 53.9% (95% CI = 49.0% to 56.3%) and 38.6% (95% CI = 34.1% to 42.0%), and for MSH6 were 12.0% (95% CI = 2.4% to 24.6%) and 12.3% (95% CI = 3.5% to 23.2%).

Conclusions

Our results provide up-to-date and comprehensive age-specific CRC risk estimates for counseling and risk prediction tools. These will have a direct clinical impact by improving prevention and management strategies for both individuals who are MMR mutation carriers and those considering testing.

Spectrum and Frequency of Tumors, Cancer Risk and Survival in Chilean Families with Lynch Syndrome: Experience of the Implementation of a Registry

Lynch syndrome (LS) is associated with the highest risk of colorectal (CRC) and several extracolonic cancers. In our effort to characterize LS families from Latin America, this study aimed to describe the spectrum of neoplasms and cancer risk by gender, age and gene, and survival in 34 Chilean LS families. Of them, 59% harbored path_MLH1, 23% path_MSH2, 12% path_PMS2 and 6% path_EPCAM variants. A total of 866 individuals at risk were identified, of which 213 (24.6%) developed 308 neoplasms. In males, CRC was the most common cancer (72.6%), while females showed a greater frequency of extracolonic cancers (58.4%), including uterus and breast (p < 0.0001). The cumulative incidence of extracolonic cancers was higher in females than males (p = 0.001). Path_MLH1 variants are significantly more associated with the development of CRC than extracolonic tumors (59.5% vs. 40.5%) when compared to path_MSH2 (47.5% vs. 52.5%) variants (p = 0.05018). The cumulative incidence of CRC was higher in path_MLH1/path_MSH2 carriers compared to path_PMS2 carriers (p = 0.03). In addition, path_MSH2 carriers showed higher risk of extracolonic tumors (p = 0.002). In conclusion, this study provides a snapshot of the LS profile from Chile and the current LS-associated diagnostic practice and output in Chile. Categorizing cancer risks associated with each population is relevant in the genetic counselling of LS patients.

Update on Hereditary Renal Cancer and Imaging Implications

Up to 8% of renal cancers are thought to have a hereditary component. Several hereditary renal cancer syndromes have been identified over the last few decades. It is important for the radiologist to be aware of findings associated with hereditary renal cancer syndromes to detect tumors early, enroll patients in appropriate surveillance programs, and improve outcomes for the patient and affected family members. This review discusses from a radiologist's perspective well-known hereditary renal cancer syndromes and emerging genetic mutations associated with renal cancer that are less well characterized, focusing on imaging features and known associations.

Cancer risks in Lynch syndrome, Lynch-like syndrome, and familial colorectal cancer type X: a prospective cohort study

Background

Individuals with pathogenic germline variants in DNA mismatch repair (MMR) genes are at increased risk of developing colorectal, endometrial and other cancers (Lynch syndrome, LS). While previous studies have extensively described cancer risks in LS, cancer risks in individuals from families without detectable MMR gene defects despite MMR deficiency (Lynch-like syndrome, LLS), and in individuals from families fulfilling the Amsterdam-II criteria without any signs of MMR deficiency (familial colorectal cancer type X, FCCX) are less well studied. The aim of this prospective study was to characterise the risk for different cancer types in LS, LLS, and FCCX, and to compare these with the cancer risks in the general population.

Methods

Data was taken from the registry of the German Consortium for Familial Intestinal Cancer, where individuals were followed up prospectively within the framework of an intensified surveillance programme at recommended annual examination intervals. A total of 1120 LS, 594 LLS, and 116 FCCX individuals were analysed. From this total sample, eight different cohorts were defined, in which age-dependent cumulative risks and standardised incidence ratios were calculated regarding the first incident occurrence of any, colorectal, stomach, small bowel, urothelial, female breast, ovarian, and endometrial cancer, separately for LS, LLS, and FCCX.

Results

The number of individuals at risk for first incident cancer ranged from 322 to 1102 in LS, 120 to 586 in LLS, and 40 to 116 in FCCX, depending on the cancer type of interest. For most cancer types, higher risks were observed in LS compared to LLS, FCCX, and the general population. Risks for any, colorectal, stomach, urothelial, and endometrial cancer were significantly higher in LLS compared to the general population. No significantly increased risks could be detected in FCCX compared to LLS patients, and the general population. Colorectal and endometrial cancer risks tended to be higher in LLS than in FCCX.

Conclusions

The characterisation of cancer risks in patients with LLS and FCCX is important to develop appropriate surveillance programmes for these specific intermediate risk groups. Larger prospective studies are needed to obtain more precise risk estimates.

Genetic testing for epithelial ovarian cancer

As the treatment of epithelial ovarian cancer (OC) moves further into personalised medicine, the importance of determining the presence or absence of inherited mutations in cancer susceptibility genes has grown. It is now becoming routine to test for germline mutations in the BRCA1 and BRCA2 genes, which are responsible for a significant proportion of hereditary epithelial OC and are established predictive biomarkers of potential benefit from poly ADP ribose polymerase (PARP) inhibitors. The identification of patients with hereditary OC allows the patient to benefit from personalised treatment, while allowing family members to undergo cascade testing, where identification of unaffected carriers can allow early detection, risk-reduction or prevention for both breast and OC, and ultimately improve long-term outcomes. Other susceptibility genes, include the Lynch Syndrome (mismatch repair) genes and several other genes involved in the homologous recombination pathway (HRD genes), are implicated in OC genesis, and are also becoming of increasing interest as therapeutic options grow for these patients. This review will highlight the importance of the early detection of a germline gene pathogenic variant, which informs on the clinical course of disease in a particular patient, and therefore, guides therapeutic management including risk reducing and personalised treatment.

Cancer Susceptibility Mutations in Patients With Urothelial Malignancies

PURPOSE

Urothelial cancers (UCs) have a substantial hereditary component, but, other than their association with Lynch syndrome, the contribution of genetic risk factors to UC pathogenesis has not been systematically defined. We sought to determine the prevalence of pathogenic/likely pathogenic (P/LP) germline variants in patients with UC and identify associated clinical factors.

PATIENTS AND METHODS

Overall, 586 patients with UC underwent prospective, matched tumor-normal DNA sequencing. Seventy-seven genes associated with cancer predisposition were analyzed; allele frequencies were compared with publicly available database.

RESULTS

P/LP germline variants were identified in 80 (14%) of 586 individuals with UC. The most common P/LP variants in high- or moderate-penetrance genes were BRCA2 (n = 9; 1.5%), MSH2 (n = 8; 1.4%), BRCA1 (n = 8; 1.4%), CHEK2 (n = 6; 1.0%), ERCC3 (n = 4; 0.7%), and NBN and RAD50 (n = 3; 0.5% each). Sixty-six patients (83%) had germline P/LP variants in DNA-damage repair (DDR) genes, of which 28 (42%) had biallelic inactivation. Patients with P/LP variants were more commonly diagnosed at an early age (22% v 6% in those without variants; P = .01). BRCA2 and MSH2 were significantly associated with an increased risk for UC (odds ratio, 3.7 [P = .004] and 4.6 [P = .001], respectively). Current clinical guidelines for referral for genetic testing failed to identify 6 (26%) patients with high-penetrance variants.

CONCLUSION

Clinically significant P/LP germline variants in DDR genes frequently are present in patients with advanced UC. The presence of DDR germline variants could guide cancer screening for patients and their families and serve as predictive biomarkers of response to targeted or immunotherapies. Family history-based criteria to identify patients with hereditary UC susceptibility are insensitive. Broader germline testing in UC, particularly in those of young ages, should be considered.

Development and Validation of a 34-Gene Inherited Cancer Predisposition Panel Using Next-Generation Sequencing

The use of genetic testing to identify individuals with hereditary cancer syndromes has been widely adopted by clinicians for management of inherited cancer risk. The objective of this study was to develop and validate a 34-gene inherited cancer predisposition panel using targeted capture-based next-generation sequencing (NGS). The panel incorporates genes underlying well-characterized cancer syndromes, such as BRCA1 and BRCA2 (BRCA1/2), along with more recently discovered genes associated with increased cancer risk. We performed a validation study on 133 unique specimens, including 33 with known variant status; known variants included single nucleotide variants (SNVs) and small insertions and deletions (Indels), as well as copy-number variants (CNVs). The analytical validation study achieved 100% sensitivity and specificity for SNVs and small Indels, with 100% sensitivity and 98.0% specificity for CNVs using in-house developed CNV flagging algorithm. We employed a microarray comparative genomic hybridization (aCGH) method for all specimens that the algorithm flags as CNV-positive for confirmation. In combination with aCGH confirmation, CNV detection specificity improved to 100%. We additionally report results of the first 500 consecutive specimens submitted for clinical testing with the 34-gene panel, identifying 53 deleterious variants in 13 genes in 49 individuals. Half of the detected pathogenic/likely pathogenic variants were found in BRCA1 (23%), BRCA2 (23%), or the Lynch syndrome-associated genes PMS2 (4%) and MLH1 (2%). The other half were detected in 9 other genes: MUTYH (17%), CHEK2 (15%), ATM (4%), PALB2 (4%), BARD1 (2%), CDH1 (2%), CDKN2A (2%), RAD51C (2%), and RET (2%). Our validation studies and initial clinical data demonstrate that a 34-gene inherited cancer predisposition panel can provide clinically significant information for cancer risk assessment.

Clinical significance of MLH1/MSH2 for stage II/III sporadic colorectal cancer

BACKGROUND

The development of colorectal cancer (CRC) is a complicated multistep process that involves an accumulation of mutations in tumor suppressor genes and oncogenes. In the process of DNA replication, base mismatch often occurs due to various factors leading to abnormal expression of mismatch repair genes (MMR), among which MLH1 and MSH2 are the most important. Recently, numerous studies indicated that MLH1/MSH2 phenotype is associated with CRC. We wanted to elucidate the role of MLH1/MSH2 in the prediction and prognosis of CRC through long-term clinical observation.

AIM

To evaluate the prognostic and predictive significance of MLH1/MSH2 in patients with stage II-III CRC using immunohistochemical analysis and GeneScan.

METHODS

Specimens from 681 patients with CRC (395 stage II and 286 stage III, 387 males and 294 females) who underwent curative surgical resection from 2013 to 2016 were tested. Immunohistochemistry was used to analyze MMR status and the microsatellite status of 133 patients was determined by GeneScan analysis.

RESULTS

Five hundred and fifty (80.76%) patients were MLH1/MSH2 positive and 131 (19.24%) were negative by immunohistochemistry. MLH1/MSH2-positive tumors were significantly more frequent in the colon than in the rectum, and had poor differentiation and less mucin production (P < 0.05). Patients of different groups did not differ in terms of age, gender, tumor size, tumor stage, lymphocytic infiltration, or circumscribed margin. MLH1/MSH2-negative patients had a more favorable OS than MLH1/MSH2-positive patients (P < 0.001). Univariate and multivariate analyses demonstrated MLH1/MSH2 expression as an independent prognostic and predictive factor for stage II/III CRC. MLH1/MSH2 expression was a strong prognostic factor in all patients [P < 0.001, hazard ratio (HR) = 4.064, 95%CI: 2.241–7.369]. Adjuvant chemotherapy had a greater correlation with survival advantage in MLH1/MSH2-negative patients with stage III disease (P < 0.001, HR = 7.660, 95%CI: 2.974–15.883). However, patients with stage II disease or MLH1/MSH2-positive patients with stage III disease did not benefit from adjuvant chemotherapy. GeneScan analysis demonstrated that among 133 patients, 105 (78.95%) were microsatellite stable, and 28 (21.05%) had microsatellite instability (MSI), including 18 (13.53%) with high MSI and 10 (7.52%) with low MSI. This is consistent with the immunohistochemical results.

CONCLUSION

MLH1/MSH2 phenotype constitutes a pathologically and clinically distinct subtype of sporadic CRC. MLH1/MSH2 is an independent prognostic and predictive factor for outcome of stage II-III CRC.

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

PURPOSE

Pathogenic 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.

METHODS

We 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.

RESULTS

There 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.

CONCLUSION

Management 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.

Hypermutagenesis in untreated adult gliomas due to inherited mismatch mutations

Hypermutagenesis refers to marked increase in the number of mutations due to continuous mutagenic process. Hypermutated tumors, have being found in several tumor types, are associated with inherited or acquired alterations in the DNA repair pathways. Hypermutation has been observed in a subset of adult glioma patients as a direct result of temozolomide(TMZ)-induced mutagenesis. In our study, we have identified a rare subset of treatment-naïve adult gliomas with de novo hypermutator phenotype and explored the evolution of spontaneous and treatment-induced hypermutagenesis. We conducted Whole-Exome Sequencing (WES), Whole-Transcriptome Sequencing (WTS), and Single-Cell Sequencing (SCS) of TMZ-naïve and post-TMZ-treated hypermutated tumors to identify distinct clinical or genomic manifestations that contribute to the development of hypermutation in untreated adult gliomas. TMZ-naïve hypermutated tumors were marked by absence of IDH1 somatic mutation and MGMT promoter (pMGMT) methylation, two genomic traits that were significantly associated with the TMZ-induced hypermutagenic event in glioblastoma, and harbored inherited alterations in the mismatch repair (MMR) machinery. The immediate family members of the TMZ-naive hypermutated glioma patients were also previous diagnosed with cancer development history, suggesting that germline dysfunction of the MMR pathway could potentially pose hereditary risk to genetic predisposition of carcinogenesis in gliomas. Lastly, both TMZ-naïve and post-TMZ-treated hypermutated tumors exhibited a significant accumulation of neoantigen loads, suggesting immunotherapeutic alternatives. Our results present new and unique understanding of hypermutagenic process in adult gliomas and an important step towards clinical implication of immunotherapy in glioma treatment.

Lynch Syndrome: Genomics Update and Imaging Review

Lynch syndrome is the most common hereditary cancer syndrome, the most common cause of heritable colorectal cancer, and the only known heritable cause of endometrial cancer. Other cancers associated with Lynch syndrome include cancers of the ovary, stomach, urothelial tract, and small bowel, and less frequently, cancers of the brain, biliary tract, pancreas, and prostate. The oncogenic tendency of Lynch syndrome stems from a set of genomic alterations of mismatch repair proteins. Defunct mismatch repair proteins cause unusually high instability of regions of the genome called microsatellites. Over time, the accumulation of mutations in microsatellites and elsewhere in the genome can affect the production of important cellular proteins, spurring tumorigenesis. Universal testing of colorectal tumors for microsatellite instability (MSI) is now recommended to (a) prevent cases of Lynch syndrome being missed owing to the use of clinical criteria alone, (b) reduce morbidity and mortality among the relatives of affected individuals, and (c) guide management decisions. Organ-specific cancer risks and associated screening paradigms vary according to the sex of the affected individual and the type of germline DNA alteration causing the MSI. Furthermore, Lynch syndrome-associated cancers have different pathologic, radiologic, and clinical features compared with their sporadic counterparts. Most notably, Lynch syndrome-associated tumors tend to be more indolent than non-Lynch syndrome-associated neoplasms and thus may respond differently to traditional chemotherapy regimens. The high MSI in cases of colorectal cancer reflects a difference in the biologic features of the tumor, possibly with a unique susceptibility to immunotherapy. ^©RSNA, 2018.

Systematic Review: An Update on the Spectrum of Urological Malignancies in Lynch Syndrome

Background:

Lynch syndrome is an autosomal dominant disorder that predisposes individuals affected to certain malignancies. Colon and endometrial cancers are the malignancies most highly associated with Lynch syndrome. However, growing body of evidence links Lynch syndrome to urological cancers.

Objective:

This review aims to clarify the type of urological malignancies that fall under the Lynch-associated cancer spectrum.

Methods:

Using PRISMA guidelines, a systematic search between January 1990 to February 2018, was conducted using the MEDLINE database with the application of the following MESH terms: colorectal neoplasms, hereditary nonpolyposis; DNA mismatch repair; urologic neoplasms; kidney pelvis; ureteral neoplasms; urinary bladder; carcinoma, transitional cell; prostatic neoplasms; testicular neoplasms.

Results:

Upper tract urothelial cancers are well established under the Lynch spectrum. Increasing evidence supports its association with prostate cancer. However, there is, inconclusive and limited evidence for an association with bladder and testicular cancer.

Conclusions:

The evidence underpinning certain urological malignancies associated with Lynch syndrome has expanded in recent years. Our review may assist in providing a summary of the current standing in literature. However, we recommend further investigations to better clarify associations, particularly with prostate, bladder and testicular cancer.

Characteristics of Lynch syndrome associated ovarian cancer

OBJECTIVE

To describe clinical characteristics of Lynch syndrome associated ovarian cancer and the efficacy of surveillance in the early detection of these ovarian cancers.

METHODS

All Lynch syndrome associated ovarian cancer cases identified in either the Dutch Lynch syndrome registry (DLSR) between 1987 and 2016, and/or the cohort at the University Medical Center Groningen (UMCG) between 1993 and 2016 were included. Clinical data on age at diagnosis, mutation type, histological type, FIGO stage, treatment, follow-up and gynecological surveillance were collected.

RESULTS

A total of 46/798 (6%) women in the DLSR and 7/80 (9%) in the UMCG cohort were identified as LS associated ovarian cancer patients. The median age at ovarian cancer diagnosis was 46.0 years (range 20-75 years). The most frequently reported histological type was endometrioid adenocarcinoma (40%; n = 21) and serous carcinoma (36%; n = 19). Most tumors (87%; n = 46) were detected at an early stage (FIGO I/II). Forty-one of 53 (77%) patients were diagnosed with ovarian cancer before LS was diagnosed. In the other 12/53 (23%) women, ovarian cancer developed after starting annual gynecological surveillance for LS; three ovarian cancers were screen-detected in asymptomatic women. Overall survival was 83%.

CONCLUSION

Ovarian cancer in women with LS has a wide age-range of onset, is usually diagnosed at an early stage with predominantly endometrioid type histology and a good overall survival. The early stage at diagnosis could not be attributed to annual gynecological surveillance.

Inherited forms of bladder cancer: a review of Lynch syndrome and other inherited conditions

Environmental factors that play a role in the urothelial carcinogenesis have been well characterized. Current research is continuously exploring potential heritable forms of bladder cancer. Lynch syndrome is a well-known inheritable disease that increases the risk for a variety of cancers, including urothelial carcinomas. Screening of patients with known Lynch syndrome is important to evaluate for development of new primary tumors. Further study may provide more information on what level of follow-up each patient needs. Recent data suggest that mismatch repair mutations confer a greater risk for urothelial cancer. Additional large patient series as well as advancement of molecular testing may provide triage for Lynch syndrome patients in regards to the frequency and type of screening best suited for individual patient.

Genetic anticipation in Swedish Lynch syndrome families

Among hereditary colorectal cancer predisposing syndromes, Lynch syndrome (LS) caused by mutations in DNA mismatch repair genes MLH1, MSH2, MSH6 or PMS2 is the most common. Patients with LS have an increased risk of early onset colon and endometrial cancer, but also other tumors that generally have an earlier onset compared to the general population. However, age at first primary cancer varies within families and genetic anticipation, i.e. decreasing age at onset in successive generations, has been suggested in LS. Anticipation is a well-known phenomenon in e.g neurodegenerative diseases and several reports have studied anticipation in heritable cancer. The purpose of this study is to determine whether anticipation can be shown in a nationwide cohort of Swedish LS families referred to the regional departments of clinical genetics in Lund, Stockholm, Linköping, Uppsala and Umeå between the years 1990–2013. We analyzed a homogenous group of mutation carriers, utilizing information from both affected and non-affected family members. In total, 239 families with a mismatch repair gene mutation (96 MLH1 families, 90 MSH2 families including one family with an EPCAM–MSH2 deletion, 39 MSH6 families, 12 PMS2 families, and 2 MLH1+PMS2 families) comprising 1028 at-risk carriers were identified among the Swedish LS families, of which 1003 mutation carriers had available follow-up information and could be included in the study. Using a normal random effects model (NREM) we estimate a 2.1 year decrease in age of diagnosis per generation. An alternative analysis using a mixed-effects Cox proportional hazards model (COX-R) estimates a hazard ratio of exp(0.171), or about 1.19, for age of diagnosis between consecutive generations. LS-associated gene-specific anticipation effects are evident for MSH2 (2.6 years/generation for NREM and hazard ratio of 1.33 for COX-R) and PMS2 (7.3 years/generation and hazard ratio of 1.86). The estimated anticipation effects for MLH1 and MSH6 are smaller.

Genetic anticipation is a phenomenon where symptoms of a hereditary disease appear at an earlier age and/or are more severe in successive generations. In genetic disorders such as Fragile X syndrome, Myotonic dystrophy type 1 and Huntington disease, anticipation is caused by the expansion of unstable trinucleotide repeats during meiosis. Anticipation is also reported to occur in some hereditary cancers though the underlying mechanism behind this observation is unknown. Several studies have investigated anticipation in Lynch syndrome, the most common hereditary colorectal cancer syndrome, yet there is a debate concerning whether anticipation occurs and what underlying mechanism there is. The objective of this project is to study if anticipation is part of the clinical picture in Swedish families with LS, with the long term goal to enable better prediction of age at onset in family members. Our results suggest that anticipation occurs in families with mutation in MSH2 and PMS2, while the evidence is equivocal for MLH1 and MSH6.

Prevalence and prognostic role of mismatch repair gene defect in endometrial cancer patients

The study was to evaluate the prevalence of mismatch repair gene defect among Thai patients with endometrial cancer and its association with clinico-pathological features and survivals. The formalin fixed paraffin-embedded blocks of EMC tissue from hysterectomy specimens of patients having surgery in our institution between 1 Jan 1995 and 31 December 2016 were assessed for the immunohistochemical expression of 4 mismatch repair proteins (MLH1, PMS, MSH2, MSH 6). Mismatch repair gene defect was determined by a negative expression of at least 1 protein. Among 385 EMC patients included in the study, mean age was 57.3 ± 10.8 years with 62.3% aged ⩽ 60 years. The most frequent mismatch repair gene defect was MSH6 (38.7%), followed by PMS2 (34.3%), MLH1 (33.2%), and MSH2 (16.4%). Overall, 55.1% showed negative expression of at least one protein. We found significantly higher mismatch repair gene defect in patients aged ⩽ 60 years, with early stage disease, and negative lymph node status than the other comparative groups: 59.2% vs 48.3% for age (p = 0.037), 58.2% vs 45.2% (p = 0.027) for stage, and 58.1% vs 44.6% (p = 0.048) for nodal status. The 5-year progression-free survival, overall survival, and endometrial cancer-specific survival of patients with mismatch repair gene defect was higher than those without gene defect. The differences were statistically significant for only progression-free survival and endometrial cancer-specific survival: 87.7% (95% confidence interval = 83.0%-92.4%) vs 81.5% (95% confidence interval = 75.4%-87.6%) (p = 0.049) for progression-free survival and 91.0% (95% confidence interval = 86.9%-95.1%) vs 85.5% (95% confidence interval = 80.0%-91.0%) (p = 0.044) for endometrial cancer-specific survival, respectively. In conclusion, more than half of Thai endometrial cancer patients had mismatch repair gene defect. The patients with mismatch repair gene defect had significantly younger age (⩽ 60 years) and better prognosis in terms of early stage, negative nodal status, and longer survivals.

Hypermutated tumours in the era of immunotherapy: The paradigm of personalised medicine

Immune checkpoint inhibitors have demonstrated unprecedented clinical activity in a wide range of cancers. Significant therapeutic responses have recently been observed in patients presenting mismatch repair-deficient (MMRD) tumours. MMRD cancers exhibit a remarkably high rate of mutations, which can result in the formation of neoantigens, hypothesised to enhance the antitumour immune response. In addition to MMRD tumours, cancers mutated in the exonuclease domain of the catalytic subunit of the DNA polymerase epsilon (POLE) also exhibit an ultramutated genome and are thus likely to benefit from immunotherapy. In this review, we provide an overview of recent data on hypermutated tumours, including MMRD and POLE-mutated cancers, with a focus on their distinctive clinicopathological and molecular characteristics as well as their immune environment. We also discuss the emergence of immune therapy to treat these hypermutated cancers, and we comment on the recent Food and Drug Administration approval of an immune checkpoint inhibitor, the programmed cell death 1 antibody (pembrolizumab, Keytruda), for the treatment of patients with metastatic MMRD cancers regardless of the tumour type. This breakthrough represents a turning point in the management of these hypermutated tumours and paves the way for broader strategies in immunoprecision medicine.

Association between the Lynch syndrome gene MSH2 and breast cancer susceptibility in a Canadian familial cancer registry

BACKGROUND

Previous studies assessing breast cancer risk in families with Lynch syndrome (LS) have yielded conflicting results. Furthermore, conclusions are limited by small sample size and few breast cancer outcomes. This study assesses breast cancer risk in a large prospectively followed LS cohort.

METHODS

Pedigrees of 325 unrelated families with LS within the Familial Gastrointestinal Cancer Registry in Canada were examined for breast cancer diagnoses. Standardised incidence ratios (SIR) and lifetime cumulative incidence calculations were used to compare the incidence of breast cancer in mutation carriers with the general population.

RESULTS

Forty-one mutation carriers diagnosed with breast cancer belonging to 34 unrelated families were identified. Mean age at diagnosis was 54 years. The mutation distribution among the LS patients with breast cancer was statistically different from those without breast cancer (p=0.015), reflecting the predominance of MSH2 mutations among affected patients (74%). Eighty-eight per cent of LS families with breast cancer met Amsterdam criteria, compared with 49% of LS families without breast cancer (p=0.03). Lifetime cumulative incidence of breast cancer in female MSH2 mutation carriers in our cohort was 22% (p<0.001). The SIR for breast cancer of female MSH2 mutation carriers in our cohort was 3.11 (95% CI 1.95 to 4.71).

CONCLUSIONS

An increased risk of breast cancer in MSH2 mutation carriers was demonstrated in a Canadian familial cancer registry. Women with breast cancer often had a personal and family history of multiple LS-related malignancies. These results suggest a potential role for intensified breast cancer surveillance among women with LS.

Prevalence of germ-line mutations in cancer genes among pancreatic cancer patients with a positive family history

Background

Panel-based genetic testing has identified increasing numbers of patients with pancreatic ductal adenocarcinoma (PDAC) who carry germline mutations. However, small sample sizes or number of genes evaluated limit prevalence estimates of these mutations. We estimated prevalence of mutations in PDAC patients with positive family history.

Methods

We sequenced 25 cancer susceptibility genes in lymphocyte DNA from 302 PDAC patients in the Mayo Clinic Biospecimen Resource for Pancreatic Research Registry. Kindreds containing at least two first-degree relatives with PDAC met criteria for Familial Pancreatic Cancer (FPC), while the remaining were familial, but not FPC.

Results

Thirty-six patients (12%) carried at least one deleterious mutation in one of 11 genes. Of FPC patients, 25/185 (14%) were carriers, while 11/117 (9%) non-FPC patients with family history were carriers. Deleterious mutations (n) identified in PDAC patients were BRCA2 (11), ATM (8), CDKN2A (4), CHEK2 (4), MUTYH/MYH (3 heterozygotes, not biallelic), BRCA1 (2), and 1 each in BARD1, MSH2, NBN, PALB2, and PMS2. Novel mutations were found in ATM, BARD1, and PMS2.

Conclusions

Multiple susceptibility gene testing in PDAC patients with family history of pancreatic cancer is warranted regardless of FPC status, and will inform genetic risk counseling for families.

Hereditary cancer registries improve the care of patients with a genetic predisposition to cancer: contributions from the Dutch Lynch syndrome registry

The Dutch Hereditary Cancer Registry was established in 1985 with the support of the Ministry of Health (VWS). The aims of the registry are: (1) to promote the identification of families with hereditary cancer, (2) to encourage the participation in surveillance programs of individuals at high risk, (3) to ensure the continuity of lifelong surveillance examinations, and (4) to promote research, in particular the improvement of surveillance protocols. During its early days the registry provided assistance with family investigations and the collection of medical data, and recommended surveillance when a family fulfilled specific diagnostic criteria. Since 2000 the registry has focused on family follow-up, and ensuring the quality of surveillance programs and appropriate clinical management. Since its founding, the registry has identified over 10,000 high-risk individuals with a diverse array of hereditary cancer syndromes. All were encouraged to participate in prevention programmes. The registry has published a number of studies that evaluated the outcome of surveillance protocols for colorectal cancer (CRC) in Lynch syndrome, as well as in familial colorectal cancer. In 2006, evaluation of the effect of registration and colonoscopic surveillance on the mortality rate associated with colorectal cancer (CRC) showed that the policy led to a substantial decrease in the mortality rate associated with CRC. Following discovery of MMR gene defects, the first predictive model that could select families for genetic testing was published by the Leiden group. In addition, over the years the registry has produced many cancer risk studies that have helped to develop appropriate surveillance protocols. Hereditary cancer registries in general, and the Lynch syndrome registry in particular, play an important role in improving the clinical management of affected families.

Update on Lynch syndrome genomics

Four main DNA mismatch repair (MMR) genes have been identified, MLH1, MSH2, MSH6, and PMS2, which when mutated cause susceptibility to Lynch syndrome (LS). LS is one of the most prevalent hereditary cancer syndromes in man and accounts for 1–3 % of unselected colorectal carcinomas and some 15 % of those with microsatellite instability and/or absent MMR protein. The International Society for Gastrointestinal Hereditary Tumours (InSiGHT) maintains a database for LS-associated mutations since 1996. The database was recently reorganized to efficiently gather published and unpublished data and to classify the variants according to a five-tiered scheme linked to clinical recommendations. This review provides an update of germline mutations causing susceptibility to LS based on information available in the InSiGHT database and the latest literature. MMR gene mutation profiles, correlations between genotype and phenotype, and possible mechanisms leading to the characteristic spectrum of tumors in LS are discussed in light of the different functions of MMR proteins, many of which directly serve cancer avoidance.

The current value of determining the mismatch repair status of colorectal cancer: A rationale for routine testing

Colorectal Cancer (CRC) is the third most prevalent cancer in men and women. Up to 15% of CRCs display microsatellite instability (MSI). MSI is reflective of a deficient mismatch repair (MMR) system and is most commonly caused by hypermethylation of the MLH1 promoter. However, it may also be due to autosomal dominant constitutional mutations in DNA MMR, termed Lynch Syndrome. MSI may be diagnosed via polymerase chain reaction (PCR) or alternatively, immunohistochemistry (IHC) can identify MMR deficiency (dMMR). Many institutions now advocate universal tumor screening of CRC via either PCR for MSI or IHC for dMMR to guide Lynch Syndrome testing. The association of sporadic MSI with methylation of the MLH1 promoter and an activating BRAF mutation may offer further exclusion criteria for genetic testing. Aside from screening for Lynch syndrome, MMR testing is important because of its prognostic and therapeutic implications. Several studies have shown MSI CRCs exhibit different clinicopathological features and prognosis compared to microsatellite-stable (MSS) CRCs. For example, response to conventional chemotherapy has been reported to be less in MSI tumours. More recently, MSI tumours have been shown to be responsive to immune-checkpoint inhibition providing a novel therapeutic strategy. This provides a rationale for routine testing for MSI or dMMR in CRC.

Epigenetics in endometrial carcinogenesis - part 2: histone modifications, chromatin remodeling and noncoding RNAs

Carcinogenesis is a multistep multifactorial process that involves the accumulation of genetic and epigenetic alterations. In the past two decades, there has been an exponential growth of knowledge establishing the importance of epigenetic changes in cancer. Our work focused on reviewing the main role of epigenetics in the pathogenesis of endometrial carcinoma, highlighting the reported results concerning each epigenetic mechanistic layer. In a previous review, we assessed DNA methylation alterations. The present review examines the contribution of histone modifications, chromatin remodeling and noncoding RNA alterations for endometrial carcinogenesis.

Comparison of lifestyle, hormonal and medical factors in women with sporadic and Lynch syndrome-associated endometrial cancer: A retrospective case-case study

Data available on lifestyle-associated hormonal and medical factors among endometrial cancer (EC)-affected women who carry the Lynch Syndrome (LS) mutation is limited. The aim of the present retrospective case study was to compare the reproductive and medical history, as well as lifestyle-associated factors, among patients with LS and sporadic EC. The study population consisted of 50 verified germline mismatch repair (MMR) gene mutation carriers diagnosed with EC, and 110 sporadic EC patients. Data were collected using postal questionnaires. Apart from the mean age at the time of the EC diagnosis (LS, 48.7 years compared with sporadic patients, 55.2 years; P<0.0001), the characteristics of sporadic and LS EC patients were similar with regard to body mass index (BMI) at age 18, 40 or at the time of the survey, and smoking and alcohol consumption. LS women reported a significantly lower rate of spontaneous abortion (P=0.043) and also more frequent use of contraceptives (P=0.004). The prevalence of co-morbidities, including diabetes, atherosclerosis, hypercholesterolemia and hypertension, was similar between the LS and the sporadic groups. A trend for a higher prevalence of endometriosis among mutation carriers was detected (16.0 vs. 8.1%, P=0.137). As anticipated, the prevalence of gastrointestinal tract, urinary tract and ovarian cancer was higher among the LS women (P<0.0001, P=0.006 and P=0.056, respectively). Co-morbidity and lifestyle-associated factors appeared to be comparable among patients with LS and sporadic EC. The reported difference in the use of contraceptives warrants further investigation. Future studies are also required to address the possible association between LS and endometriosis.

Cancer incidence and survival in Lynch syndrome patients receiving colonoscopic and gynaecological surveillance: first report from the prospective Lynch syndrome database

OBJECTIVE

Estimates of cancer risk and the effects of surveillance in Lynch syndrome have been subject to bias, partly through reliance on retrospective studies. We sought to establish more robust estimates in patients undergoing prospective cancer surveillance.

DESIGN

We undertook a multicentre study of patients carrying Lynch syndrome-associated mutations affecting MLH1, MSH2, MSH6 or PMS2. Standardised information on surveillance, cancers and outcomes were collated in an Oracle relational database and analysed by age, sex and mutated gene.

RESULTS

1942 mutation carriers without previous cancer had follow-up including colonoscopic surveillance for 13 782 observation years. 314 patients developed cancer, mostly colorectal (n=151), endometrial (n=72) and ovarian (n=19). Cancers were detected from 25 years onwards in MLH1 and MSH2 mutation carriers, and from about 40 years in MSH6 and PMS2 carriers. Among first cancer detected in each patient the colorectal cancer cumulative incidences at 70 years by gene were 46%, 35%, 20% and 10% for MLH1, MSH2, MSH6 and PMS2 mutation carriers, respectively. The equivalent cumulative incidences for endometrial cancer were 34%, 51%, 49% and 24%; and for ovarian cancer 11%, 15%, 0% and 0%. Ten-year crude survival was 87% after any cancer, 91% if the first cancer was colorectal, 98% if endometrial and 89% if ovarian.

CONCLUSIONS

The four Lynch syndrome-associated genes had different penetrance and expression. Colorectal cancer occurred frequently despite colonoscopic surveillance but resulted in few deaths. Using our data, a website has been established at http://LScarisk.org enabling calculation of cumulative cancer risks as an aid to genetic counselling in Lynch syndrome.

Update on immune checkpoint inhibitors in gynecological cancers

In recent years, progress in our understanding of immune-modulatory signaling pathways in immune cells and the tumor microenvironment (TME) has led to rejuvenated interest in cancer immunotherapy. In particular, immunotherapy targeting the immune checkpoint receptors such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell-death 1 (PD-1), and programmed cell-death ligand 1 (PD-L1) have demonstrated clinical activity in a wide variety of tumors, including gynecological cancers. This review will focus on the emerging clinical data on the therapeutic role of immune checkpoint inhibitors, and potential strategies to enhance the efficacy of this class of compounds, in the context of gynecological cancers. It is anticipated that future biomarker-directed clinical trials will provide further insights into the mechanisms underlying response and resistance to immunotherapy, and help guide our approach to designing therapeutic combinations that have the potential to enhance the benefit of immunotherapy in patients with gynecologic cancers.

Molecular Subtypes of Colorectal Cancer and Their Clinicopathologic Features, With an Emphasis on the Serrated Neoplasia Pathway

CONTEXT

-Colorectal cancer is a heterogeneous disease entity with 3 molecular carcinogenesis pathways and 2 morphologic multistep pathways. Right-sided colon cancers and left-sided colon and rectal cancers exhibit differences in their incidence rates according to geographic region, age, and sex. A linear tendency toward increasing frequencies of microsatellite instability-high or CpG island methylator phenotype-high cancers in subsites along the bowel from the rectum to the cecum or the ascending colon accounts for the differences in tumor phenotypes associated with these subsites. The molecular subtypes of colorectal cancers exhibit different responses to adjuvant therapy, which might be responsible for differences in subtype-specific survival.

OBJECTIVES

-To review the clinicopathologic and molecular features of the molecular subtypes of colorectal cancer generated by combined CpG island methylator phenotype and microsatellite statuses, to integrate these features with the most recent findings in the context of the prognostic implications of molecular subtypes, and to emphasize the necessity of developing molecular markers that enable the identification of adenocarcinomas involving the serrated neoplasia pathway.

DATA SOURCES

-Based on the authors' own experimental data and a review of the pertinent literature.

CONCLUSIONS

-Because colorectal cancers arise from 2 different morphologic multistep carcinogenesis pathways with varying contributions from 3 different molecular carcinogenesis pathways, colorectal cancer is a heterogeneous and complex disease. Thus, molecular subtyping of colorectal cancers is an important approach to characterizing their heterogeneity with respect to not only prognosis and therapeutic response but also biology and natural history.

Distinct expression profile of lncRNA in endometrial carcinoma

Endometrial carcinoma (EC) is the most common malignancy in women. Dispite its prevalence, the prognosis of endometrial carcinoma still relies on conventional histological type, grade and invasion information. Its morbidity is still increasing and the outcome is very poor. To the best of our knowledge, hormonal imbalance and/or molecular genetic alterations are the main cause of EC. However, the alterations of lncRNAs which accounts for approximately 4/5 of human transcripts are still poorly understood. In the present study, using the RiboArray™ Custom Array, we studied the expression profiles of lncRNA in EC as compared to normal endometrium (NE) to find potential core lncRNAs for the diagnosis of EC. We found the potential core lncRNA by GO, KEGG, lncRNA and mRNA co-expression network. The potential functional lncRNAs were further detected by qPCR to validate the microarray results. A total of 172 lncRNAs and 188 mRNAs were found to be differentially expressed between type Ⅰ EC and the NE samples (fold change >1.5). qPCR validation showed good consistency with the microarray data. GO, pathway analysis, the lncRNA and mRNA co-expression network as well as the TCGA data revealed that 6 lncRNAs (KIAA0087, RP11-501O2, FAM212B-AS1, LOC102723552, RP11-140I24 and RP11-600K151) may be the core regulators of endometrial carcinogenesis. The potential core lncRNAs revealed by the mRNA and lncRNA co-expression network might be helpful to explore potential early diagnostic and therapeutic targets for EC.

Evaluation of Metachronous Breast and Endometrial Cancers: Preroutine and Postroutine Adjuvant Tamoxifen Use

BACKGROUND

The time interval between diagnoses of breast cancer (BC) and endometrial cancer (EC) is not well established in women with metachronous primary tumors. We sought to examine this interval and identify associations with treatment-related and clinicopathologic factors.

METHODS

We identified 141 patients who developed both cancers during 1966 to 2013. Patients were divided into 2 groups: group 1, BC first, and group 2, EC first. Subanalysis performed of group 1 (59 patients) stratified around adjuvant tamoxifen use: pre-1990 BC diagnosis and post.

RESULTS

Fifty-nine and 82 patients were in groups 1 and 2, respectively. The mean time interval was comparable (76 vs 74 months, P = 0.861). Subanalysis divided group 1 into pre- (n = 27) and post- (n = 32) 1990 and resulted in different mean time intervals between diagnosis of metachronous cancers (106 vs 50 months, respectively [P = 0.042]). Median progression-free survival (PFS) and overall survival (OS) for EC were longer in the pre group (PFS, 51 vs 26 months [P = 0.169]; OS, 59 vs 27 months [P = 0.190]). Median PFS and OS for BC were also longer in this group (PFS, 147 vs 109 months [P = 0.005]; OS, 166 vs 114 months [P < 0.001]).

CONCLUSIONS

Our data indicate the mean time interval between the diagnosis of EC and BC was approximately 6 years. Disease-specific EC survival was worse for patients with a previous diagnosis of BC. Stratification around implementation of tamoxifen use shows comparable grade and stage but different time interval and survival, suggesting resulting effects from adjuvant therapy for BC. These results are useful in counseling women at risk.

Frequent mismatch-repair defects link prostate cancer to Lynch syndrome

BACKGROUND

A possible role for prostate cancer in Lynch syndrome has been debated based on observations of mismatch-repair defective tumors and reports of an increased risk of prostate cancer in mutation carriers. Potential inclusion of prostate cancer in the Lynch syndrome tumor spectrum is relevant for family classification, risk estimates and surveillance recommendations in mutation carriers.

METHODS

We used the population-based Danish HNPCC-register to identify all prostate cancers that developed in mutation carriers and in their first-degree relatives from 288 Lynch syndrome families. The tumors were evaluated for clinicopathologic features and mismatch-repair status, and the cumulative risk of prostate cancer was determined.

RESULTS

In total, 28 prostate cancers developed in 16 mutation carriers and in 12 first-degree relatives at a median age of 63 years. The majority of the tumors were high-grade tumors with Gleason scores 8-10. Prostate cancer was associated with mutations in MSH2, MLH1 and MSH6 with loss of the respective mismatch repair protein in 69 % of the tumors, though a MSI-high phenotype was restricted to 13 % of the tumors. The cumulative risk of prostate cancer at age 70 was 3.7 % (95 % CI: 2.3-4.9).

CONCLUSION

We provide evidence to link prostate cancer to Lynch syndrome through demonstration of MMR defective tumors and an increased risk of the disease, which suggests that prostate cancer should be considered in the diagnostic work-up of Lynch syndrome.

Review: Clinical aspects of hereditary DNA Mismatch repair gene mutations

Inherited mutations of the DNA Mismatch repair genes MLH1, MSH2, MSH6 and PMS2 can result in two hereditary tumor syndromes: the adult-onset autosomal dominant Lynch syndrome, previously referred to as Hereditary Non-Polyposis Colorectal Cancer (HNPCC) and the childhood-onset autosomal recessive Constitutional Mismatch Repair Deficiency syndrome. Both conditions are important to recognize clinically as their identification has direct consequences for clinical management and allows targeted preventive actions in mutation carriers. Lynch syndrome is one of the more common adult-onset hereditary tumor syndromes, with thousands of patients reported to date. Its tumor spectrum is well established and includes colorectal cancer, endometrial cancer and a range of other cancer types. However, surveillance for cancers other than colorectal cancer is still of uncertain value. Prophylactic surgery, especially for the uterus and its adnexa is an option in female mutation carriers. Chemoprevention of colorectal cancer with aspirin is actively being investigated in this syndrome and shows promising results. In contrast, the Constitutional Mismatch Repair Deficiency syndrome is rare, features a wide spectrum of childhood onset cancers, many of which are brain tumors with high mortality rates. Future studies are very much needed to improve the care for patients with this severe disorder.