Frequency of mutations in mismatch repair genes in a population-based study of women with ovarian cancer

Comprehensive molecular assessment of mismatch repair deficiency in Lynch associated ovarian cancers using next generation sequencing panel

OBJECTIVES

Abnormalities in mismatch repair have been described in ovarian cancer, but few studies have examined the causes of mismatch repair deficiency (MMRd). To address this, we completed targeted mutational and methylation sequencing on MMRd ovarian cancer cases. The objective of this study was to explore the molecular mechanism of MMRd using our targeted next generation sequencing panel.

METHODS

Newly diagnosed non-serous/mucinous ovarian cancers (n=215) were prospectively recruited from three cancer centers in Ontario, Canada, between 2015 and 2018. Tumors were reflexively assessed for mismatch repair protein by immunohistochemistry. Matched tumor-normal MMRd cases were analyzed on a custom next generation sequencing panel to identify germline and somatic mutations, copy number variants, rearrangements, and promoter methylation in mismatch repair and associated genes.

RESULTS

Of 215 cases, 28 (13%) were MMRd. The MMRd cohort had a median age of 52.3 years (range 33.6-62.2), with mostly stage I (50%) and grade 1 or 2 endometrioid histotype (57%). Of the 28 cases, 22 were available for molecular analysis, and Lynch syndrome was detected in 50% of MMRd cases (11/22; seven ovarian cancer and four synchronous ovarian and endometrial cancer: seven MSH6, two MLH1, one PMS2, and one MSH2). An explanation for the observed mismatch repair phenotype was available for 22/22 deficient cases, including 12 MLH1/PMS2 deficient (nine somatic methylation, one bi-allelic somatic deletion, and two pathogenic germline variant), one PMS2 deficient (one pathogenic germline variant), seven MSH6 deficient (seven pathogenic germline variant), and two MSH2/MSH6 deficient (one pathogenic germline variant and one bi-allelic somatic mutation). Concordance between clinical germline testing and panel sequencing results was 100%.

CONCLUSIONS

Use of our custom next generation sequencing panel allowed for the streamlined assessment of hereditary and somatic causes of MMRd in ovarian cancers.

An epigenetic hypothesis for ovarian cancer prevention by oral contraceptive pill use

BACKGROUND

Ovarian cancer is the second most common gynecological cancer type after uterine cancers. In 2020, according to worldwide statistics, there were more than 313,000 new cases of ovarian cancer. Most concerning with ovarian cancer is the poor overall survival, with only 30% of patients surviving for longer than 5 years after diagnosis. The reason for this poor outcome includes late diagnosis due to non-specific symptoms and a lack of any highly effective biomarkers of the early stages of ovarian carcinogenesis. However, it is important to note that some modifiable lifestyle factors can be preventative [pregnancy, breastfeeding and combined oral contraceptives pill (COCP) use].

RESULTS

There is now increasing data reporting the role of epigenetic changes, which are detectable in ovarian cancer tumors, suggesting the possibility that epigenetics may also play a key role in the mechanism of long-term effective prevention of ovarian cancer. To our knowledge, there is a lack of high-quality data on the molecular mechanisms of ovarian cancer prevention, although several hypotheses have been proposed.

CONCLUSIONS

This review focusses on the evidence for a proposed novel hypothesis-that COCPs act as a chemoprevention through the impact on the epigenome of the cells of origin of ovarian cancer-fallopian tubes epithelium.

Mismatch-repair deficiency, microsatellite instability, and lynch syndrome in ovarian cancer: A systematic review and meta-analysis

OBJECTIVE

Investigating for mismatch repair protein deficiency (MMRd), microsatellite instability (MSI), and Lynch syndrome (LS) is widely accepted in endometrial cancer, but knowledge is limited on its value in epithelial ovarian cancer (EOC). The primary objective was to evaluate the prevalence of mismatch repair protein deficiency (MMRd), microsatellite instability (MSI)-high, and Lynch syndrome (LS) in epithelial ovarian cancer (EOC), as well as the diagnostic accuracy of LS screening tests. The secondary objective was to determine the prevalence of MMRd, MSI-high, and LS in synchronous ovarian endometrial cancer and in histological subtypes.

METHODS

We systematically searched the MEDLINE, Epub Ahead of Print, MEDLINE In-Process and Other Non-Indexed Citations, Cochrane Central Register of Controlled Trials, and Embase databases. We included studies analysing MMR, MSI, and/or LS by sequencing.

RESULTS

A total of 55 studies were included. The prevalence of MMRd, MSI-high, and LS in EOC was 6% (95% confidence interval (CI) 5-8%), 13% (95% CI 12-15%), and 2% (95% CI 1-3%) respectively. Hypermethylation was present in 76% of patients with MLH1 deficiency (95% CI 64-84%). The MMRd prevalence was highest in endometrioid (12%) followed by non-serous non-mucinous (9%) and lowest in serous (1%) histological subtypes. MSI-high prevalence was highest in endometrioid (12%) and non-serous non-mucinous (12%) and lowest in serous (9%) histological subtypes. Synchronous and endometrioid EOC had the highest prevalence of LS pathogenic variants at 7% and 3% respectively, with serous having lowest prevalence (1%). Synchronous ovarian and endometrial cancers had highest rates of MMRd (28%) and MSI-high (28%). Sensitivity was highest for IHC (91.1%) and IHC with MSI (92.8%), while specificity was highest for IHC with methylation (92.3%).

CONCLUSION

MMRd and germline LS testing should be considered for non-serous non-mucinous EOC, particularly for endometrioid.

PRECIS

The rates of mismatch repair deficiency, microsatellite instability high, and mismatch repair germline mutations are highest in endometrioid subtype and non-serous non-mucinous ovarian cancer. The rates are lowest in serous histologic subtype.

A Previously Unrecognized Molecular Landscape of Lynch Syndrome in the Mexican Population

Lynch syndrome (LS) is the main hereditary colorectal cancer syndrome. There have been few reports regarding the clinical and molecular characteristics of LS patients in Latin America; this is particularly true in the Mexican population, where no information is available. The present study aims to describe the clinical and molecular spectrum of variants in a cohort of patients diagnosed with LS in Mexico. We present a retrospective analysis of 412 patients with suspected LS, whose main site of cancer diagnosis was the colon (58.25%), followed by the endometrium (18.93%). Next-generation sequencing analysis, with an extensive multigene panel, showed that 27.1% (112/414) had a variant in one of the genes of the mismatch repair pathway (MMR); 30.4% (126/414) had a variant in non-MMR genes such as CHEK2, APC, MUTYH, BRCA1, and BRCA2; and 42.5% (176/414) had no genetic variants. Most of the variants were found in MLH1. Pathogenic variants (PVs) in MMR genes were identified in 65.7% (96/146) of the total PVs, and 34.24% (45/146) were in non-MMR genes. Molecular and clinical characterization of patients with LS in specific populations allowed personalized follow-up, with the option for targeted treatment with immune checkpoint inhibitors and the development of public health policies. Moreover, such characterization allows for family cascade testing and consequent prevention strategies.

Hereditary Ovarian Cancer: Towards a Cost-Effective Prevention Strategy

Ovarian cancer (OC) is the most lethal gynaecological malignancy. The search for a widely affordable and accessible screening strategy to reduce mortality from OC is still ongoing. This coupled with the late-stage presentation and poor prognosis harbours significant health-economic implications. OC is also the most heritable of all cancers, with an estimated 25% of cases having a hereditary predisposition. Advancements in technology have detected multiple mutations, with the majority affecting the BRCA1 and/or BRCA2 genes. Women with BRCA mutations are at a significantly increased lifetime risk of developing OC, often presenting with a high-grade serous pathology, which is associated with higher mortality due to its aggressive characteristic. Therefore, a targeted, cost-effective approach to prevention is paramount to improve clinical outcomes and mortality. Current guidelines offer multiple preventive strategies for individuals with hereditary OC (HOC), including genetic counselling to identify the high-risk women and risk-reducing interventions (RRI), such as surgical management or chemoprophylaxis through contraceptive medications. Evidence for sporadic OC is abundant as compared to the existing dearth in the hereditary subgroup. Hence, our review article narrates an overview of HOC and explores the RRI developed over the years. It attempts to compare the cost effectiveness of these strategies with women of the general population in order to answer the crucial question: what is the most prudent clinically and economically effective strategy for prevention amongst high-risk women?

Frequency and clinical features of deficient mismatch repair in ovarian clear cell and endometrioid carcinoma

Objective

To clarify the frequency of deficient mismatch repair (dMMR) in Japanese ovarian cancer patients, we examined microsatellite instability (MSI) status and immunohistochemistry (IHC) subtypes, including endometrioid carcinoma (EMC), clear cell carcinoma (CCC), or a mixture of both (Mix).

Methods

We registered 390 patients who were diagnosed with EMC/CCC/Mix between 2006 and 2015 and treated at seven participating facilities. For 339 patients confirmed eligible by the Central Pathological Review Board, MSI, IHC, and MutL homolog 1 methylation analyses were conducted. The tissues of patients with Lynch syndrome (LS)-related cancer histories, such as colorectal and endometrial cancer, were also investigated.

Results

MSI-high (MSI-H) status was observed in 2/217 CCC (0.9%), 10/115 EMC (8.7%), and 1/4 Mix (25%). Additionally, loss of MMR protein expression (LoE-MMR) was observed in 5/219 (2.3%), 16/115 (14.0%), and 1/4 (25%) patients with CCC, EMC, and Mix, respectively. Both MSI-H and LoE-MMR were found significantly more often in EMC (p<0.001). The median (range) ages of patients with MMR expression and LoE-MMR were 54 (30–90) and 46 (22–76) (p=0.002), respectively. In the multivariate analysis, advanced stage and histological type were identified as prognostic factors.

Conclusion

The dMMR rate for EMC/CCC was similar to that reported in Western countries. In Japan, it is assumed that the dMMR frequency is higher because of the increased proportion of CCC.

The deficient mismatch repair (dMMR) rate in Japanese patients is currently unknown. This study determined the frequency of dMMR in Japanese ovarian cancer patients. The dMMR rate was similar to that reported in Western countries. We identified potential criteria for implementing microsatellite instability and immunohistochemistry analyses in Lynch syndrome screening.

Multiple primary melanoma in association with other personal and familial cancers

BACKGROUND

Multiple primary melanoma (MPM) is known to be associated with familial melanoma. However, the association between MPM and other personal and familial cancers is not well documented. The objective of this study was to evaluate the association between MPM and personal history of other cancers or cancer history among first-degree relatives (FDRs).

METHODS

We performed a retrospective case-control study including cases with gender-matched MPM and single primary melanoma (SPM) at a 1:2 ratio from the University of Pittsburgh Cancer Institute Melanoma Center Biological Sample and Nevus Bank. The associations between MPM and other cancers were evaluated using univariable and multivariable logistic regression models.

RESULTS

In total, 378 patients (44.2% men; median age 52 years) were enrolled, including 252 with SPM and 126 with MPM. In comparison to patients with SPM, patients with MPM were more likely to have squamous cell carcinoma (odds ratio [OR] 1.95, 95% confidence interval [CI] 1.001-3.79, p = 0.047) and prostate cancer (OR 2.72, 95% CI 1.07-7.01, p = 0.034). FDRs of patients with MPM had higher prevalence of melanoma (OR 2.37, 95% CI 1.31-4.28, p = 0.004) and prostate cancer (OR 2.92, 95% CI 1.47-6.14, p = 0.002) but not other cancers. In multivariable analysis, the association remained significant between MPM and squamous cell carcinoma (OR 2.18, 95% CI 1.08-4.39, p = 0.028), prostate cancer (OR 2.85, 95% CI 1.09-7.54, p = 0.032), FDR history of melanoma (OR 2.37, 95% CI 1.31-4.29, p = 0.004), and FDR history of prostate cancer (OR 3.26, 95% CI 1.59-6.83, p = 0.001).

CONCLUSIONS

Patients with MPM have a higher prevalence of personal and FDR histories of nonmelanoma skin cancers and prostate cancer.

Epithelial Ovarian Cancer: Providing Evidence of Predisposition Genes

Epithelial ovarian cancer (EOC) is one of the cancers most influenced by hereditary factors. A fourth to a fifth of unselected EOC patients carry pathogenic variants (PVs) in a number of genes, the majority of which encode for proteins involved in DNA mismatch repair (MMR) pathways. PVs in BRCA1 and BRCA2 genes are responsible for a substantial fraction of hereditary EOC. In addition, PV genes involved in the MMR pathway account for 10–15% of hereditary EOC. The identification of women with homologous recombination (HR)-deficient EOCs has significant clinical implications, concerning chemotherapy regimen planning and development as well as the use of targeted therapies such as poly(ADP-ribose) polymerase (PARP) inhibitors. With several genes involved, the complexity of genetic testing increases. In this context, next-generation sequencing (NGS) allows testing for multiple genes simultaneously with a rapid turnaround time. In this review, we discuss the EOC risk assessment in the era of NGS.

Comprehensive epithelial tubo-ovarian cancer risk prediction model incorporating genetic and epidemiological risk factors

BACKGROUND

Epithelial tubo-ovarian cancer (EOC) has high mortality partly due to late diagnosis. Prevention is available but may be associated with adverse effects. A multifactorial risk model based on known genetic and epidemiological risk factors (RFs) for EOC can help identify women at higher risk who could benefit from targeted screening and prevention.

METHODS

We developed a multifactorial EOC risk model for women of European ancestry incorporating the effects of pathogenic variants (PVs) in BRCA1, BRCA2, RAD51C, RAD51D and BRIP1, a Polygenic Risk Score (PRS) of arbitrary size, the effects of RFs and explicit family history (FH) using a synthetic model approach. The PRS, PV and RFs were assumed to act multiplicatively.

RESULTS

Based on a currently available PRS for EOC that explains 5% of the EOC polygenic variance, the estimated lifetime risks under the multifactorial model in the general population vary from 0.5% to 4.6% for the first to 99th percentiles of the EOC risk distribution. The corresponding range for women with an affected first-degree relative is 1.9%-10.3%. Based on the combined risk distribution, 33% of RAD51D PV carriers are expected to have a lifetime EOC risk of less than 10%. RFs provided the widest distribution, followed by the PRS. In an independent partial model validation, absolute and relative 5-year risks were well calibrated in quintiles of predicted risk.

CONCLUSION

This multifactorial risk model can facilitate stratification, in particular among women with FH of cancer and/or moderate-risk and high-risk PVs. The model is available via the CanRisk Tool (www.canrisk.org).

Impact of germline mutations in cancer-predisposing genes on long-term survival in patients with epithelial ovarian cancer

BACKGROUND

Several clinical and tumour factors impact on ovarian cancer survival. It is important to evaluate if germline mutations impact long-term outcomes among patients with epithelial ovarian cancer.

METHODS

We followed 1422 Ontario women with ovarian cancer. Clinical information was obtained from medical records and vital status was determined by registry linkage. Germline genetic testing was performed for 12 susceptibility genes. We estimated 20-year cancer-specific survival according to various factors.

RESULTS

Twenty-year survival was inferior for women with serous cancers vs. other types (22.3% vs. 68.6%; P < 0.0001). Of the 1422 patients, 248 (17.4%) carried a germline mutation; 119 BRCA1; 75 BRCA2; 7 in a mismatch repair (MMR) gene and 47 in one of seven other genes. Among serous patients, 20-year survival was 28.9% for similar for women with a BRCA1 (28.9%), BRCA2 (21.2%) or no mutation (21.6%). Among endometrioid patients, 20-year survival was poor for women with a BRCA vs. no mutation (47.3% vs. 70.4%; P = 0.004). Six of the seven MMR mutation carriers are currently alive, while all three PALB2 mutation carriers died within 3 years of diagnosis. Among women with Stage III/IV serous cancers, 20-year survival was 9.4% for those with vs. 46.5% for those with no residual disease (HR = 2.91; 95% CI 2.12-4.09, P < 0.0001).

CONCLUSIONS

The most important predictor of long-term survival was no residual disease post surgery. BRCA mutation status was not predictive of long-term survival while those with MMR mutations had excellent survival. Larger studies on PALB2 carriers are needed.

The prevalence of mismatch repair deficiency in ovarian cancer: a systematic review and meta‐analysis

Ovarian cancer (OC) is the least survivable gynecological malignancy and presents late. Five‐year survival for OC is around 45% increasing the need for innovative treatments. Checkpoint inhibitors have shown significant clinical efficacy in mismatch repair deficient (MMRd) cancers and could be a powerful treatment in OC. However, their application in OC is limited due to the lack of data on the prevalence of MMRd. The aim of our study was to conduct a systematic review of the literature and meta‐analysis to provide an accurate estimate of the prevalence of MMRd in OC. We followed PRISMA guidelines throughout. Studies were identified by electronic searches of Medline, Embase, Cochrane CENTRAL and Web of Science followed by citation searching. Studies not written in English were excluded. All studies were reviewed by at least two independent reviewers. Proportions of test positivity were calculated by random and fixed‐effects meta‐analysis models. I² score was used to assess heterogeneity across studies. In total 54 studies were included with 17 532 analyzed for MMRd. The overall proportions of MMRd by immunohistochemistry and microsatellite instability analysis were 6.7% and 10.4%, respectively. MMRd was reported in all histotypes of epithelial OC but was most common in endometrioid OC. We estimate that on average 46.7% (95% CI: 28.8‐65.4) of ovarian carcinomas showing MMRd by IHC had a germline path_MMR variant identified. OC in those with Lynch syndrome seems to present at an earlier age and stage. Studies however were generally of low quality and there was a high degree of heterogeneity. A significant minority (up to 16%) of OC displays MMRd and, therefore, could be amenable to checkpoint inhibition therapy. However, the current literature base is of limited quality and therefore high‐quality prospective studies exploring MMRd in OC with the use of multimodal testing are required. In addition, trials researching efficacy of checkpoint inhibition in MMRd OC are needed.

Synonymous Variants: Necessary Nuance in our Understanding of Cancer Drivers and Treatment Outcomes

Once called "silent mutations" and assumed to have no effect on protein structure and function, synonymous variants are now recognized to be drivers for some cancers. There have been significant advances in our understanding of the numerous mechanisms by which synonymous single nucleotide variants (sSNVs) can affect protein structure and function by affecting pre-mRNA splicing, mRNA expression, stability, folding, miRNA binding, translation kinetics, and co-translational folding. This review highlights the need for considering sSNVs in cancer biology to gain a better understanding of the genetic determinants of human cancers and to improve their diagnosis and treatment. We surveyed the literature for reports of sSNVs in cancer and found numerous studies on the consequences of sSNVs on gene function with supporting in vitro evidence. We also found reports of sSNVs that have statistically significant associations with specific cancer types but for which in vitro studies are lacking to support the reported associations. Additionally, we found reports of germline and somatic sSNVs that were observed in numerous clinical studies and for which in silico analysis predicts possible effects on gene function. We provide a review of these investigations and discuss necessary future studies to elucidate the mechanisms by which sSNVs disrupt protein function and are play a role in tumorigeneses, cancer progression, and treatment efficacy. As splicing dysregulation is one of the most well recognized mechanisms by which sSNVs impact protein function, we also include our own in silico analysis for predicting which sSNVs may disrupt pre-mRNA splicing.

Implementation of Multigene Germline and Parallel Somatic Genetic Testing in Epithelial Ovarian Cancer: SIGNPOST Study

We present findings of a cancer multidisciplinary-team (MDT) coordinated mainstreaming pathway of unselected 5-panel germline BRCA1/BRCA2/RAD51C/RAD51D/BRIP1 and parallel somatic BRCA1/BRCA2 testing in all women with epithelial-OC and highlight the discordance between germline and somatic testing strategies across two cancer centres. Patients were counselled and consented by a cancer MDT member. The uptake of parallel multi-gene germline and somatic testing was 97.7%. Counselling by clinical-nurse-specialist more frequently needed >1 consultation (53.6% (30/56)) compared to a medical (15.0% (21/137)) or surgical oncologist (15.3% (17/110)) (p < 0.001). The median age was 54 (IQR = 51-62) years in germline pathogenic-variant (PV) versus 61 (IQR = 51-71) in BRCA wild-type (p = 0.001). There was no significant difference in distribution of PVs by ethnicity, stage, surgery timing or resection status. A total of 15.5% germline and 7.8% somatic BRCA1/BRCA2 PVs were identified. A total of 2.3% patients had RAD51C/RAD51D/BRIP1 PVs. A total of 11% germline PVs were large-genomic-rearrangements and missed by somatic testing. A total of 20% germline PVs are missed by somatic first BRCA-testing approach and 55.6% germline PVs missed by family history ascertainment. The somatic testing failure rate is higher (23%) for patients undergoing diagnostic biopsies. Our findings favour a prospective parallel somatic and germline panel testing approach as a clinically efficient strategy to maximise variant identification. UK Genomics test-directory criteria should be expanded to include a panel of OC genes.

Maximizing cancer prevention through genetic navigation for Lynch syndrome detection in women with newly diagnosed endometrial and nonserous/nonmucinous epithelial ovarian cancer

BACKGROUND

Despite recommendations for reflex immunohistochemistry (IHC) for mismatch repair (MMR) proteins to identify Lynch syndrome (LS), the uptake of genetic assessment by those who meet referral criteria is low. The authors implemented a comprehensive genetic navigation program to increase the uptake of genetic testing for LS in patients with endometrial cancer (EC) or nonserous/nonmucinous ovarian cancer (OC).

METHODS

Participants with newly diagnosed EC or OC were prospectively recruited from 3 cancer centers in Ontario, Canada. Family history questionnaires were used to assess LS-specific family history. Reflex IHC for MMR proteins was performed with the inclusion of clinical directives in pathology reports. A trained genetic navigator initiated a genetic referral on behalf of the treating physician and facilitated genetic referrals to the closest genetics center.

RESULTS

A total of 841 participants (642 with EC, 172 with OC, and 27 with synchronous EC/OC) consented to the study; 194 (23%) were MMR-deficient by IHC. Overall, 170 women (20%) were eligible for a genetic assessment for LS: 35 on the basis of their family history alone, 24 on the basis of their family history and IHC, 82 on the basis of IHC alone, and 29 on the basis of clinical discretion. After adjustments for participants who died (n = 6), 149 of 164 patients (91%) completed a genetic assessment, and 111 were offered and completed genetic testing. Thirty-four women (4.0% of the total cohort and 30.6% of those with genetic testing) were diagnosed with LS: 5 with mutL homolog 1 (MLH1), 9 with mutS homolog 2 (MSH2), 15 with mutS homolog 6 (MSH6), and 5 with PMS2.

CONCLUSIONS

The introduction of a navigated genetic program resulted in a high rate of genetic assessment (>90%) in patients with gynecologic cancer at risk for LS.

Frequency of germline BRCA1/2 mutations and association with clinicopathological characteristics in Turkish women with epithelial ovarian cancer

AIM

This study aims to determine the frequency of germline BRCA 1/2 mutations in Turkish women with epithelial ovarian cancer (EOC) and evaluate its relationship with clinicopathological characteristics.

METHODS

In this cross-sectional study, all women with recently diagnosed EOC presenting to Zekai Tahir Burak Women's Health Training and Research Hospital Medical Oncology Clinic between 2016 and 2019 were referred for BRCA testing. Peripheral blood samples were obtained from 76 patients applying to Medical Genetics and BRCA1/2 genes were sequenced using next-generation sequencing. The American College of Medical Genetics and Genomics 2015 criteria were followed for classification of genetic variants.

RESULTS

Twenty-four women (31.6%) had pathogenic germline BRCA1/2 mutations. Of these, 17 patients (22.4%) harbored germline BRCA1 mutations and 7 (9.2%) had BRCA2 mutations. When we compared the patients with and without BRCA mutations, there was significant difference in terms of family history (41.7% vs 9.6%, respectively, P = .001). Among all patients, 15 (19.7%) had history of breast or ovarian cancer in first- or second-degree relatives. Germline BRCA1/2 mutations were detected in 66.7% of patients with family history, while these mutations were found in 22.9% of patients without family history (P = .001).

CONCLUSION

In this sample 31.6% of Turkish women with EOC harbored germline BRCA1/2 mutations, which seems higher compared to other ethnic groups except for the Ashkenazi Jews population. All women with EOC should be referred for BRCA testing regardless of family history, age at diagnosis, and histological subtype.

How Should We Test for Lynch Syndrome? A Review of Current Guidelines and Future Strategies

International guidelines for the diagnosis of Lynch syndrome (LS) recommend molecular screening of colorectal cancers (CRCs) to identify patients for germline mismatch repair (MMR) gene testing. As our understanding of the LS phenotype and diagnostic technologies have advanced, there is a need to review these guidelines and new screening opportunities. We discuss the barriers to implementation of current guidelines, as well as guideline limitations, and highlight new technologies and knowledge that may address these. We also discuss alternative screening strategies to increase the rate of LS diagnoses. In particular, the focus of current guidance on CRCs means that approximately half of Lynch-spectrum tumours occurring in unknown male LS carriers, and only one-third in female LS carriers, will trigger testing for LS. There is increasing pressure to expand guidelines to include molecular screening of endometrial cancers, the most frequent cancer in female LS carriers. Furthermore, we collate the evidence to support MMR deficiency testing of other Lynch-spectrum tumours to screen for LS. However, a reliance on tumour tissue limits preoperative testing and, therefore, diagnosis prior to malignancy. The recent successes of functional assays to detect microsatellite instability or MMR deficiency in non-neoplastic tissues suggest that future diagnostic pipelines could become independent of tumour tissue.

Comparison of universal screening in major lynch-associated tumors: a systematic review of literature

Lynch syndrome (LS) is associated with an increased lifetime risk of several cancers including colorectal (CRC), endometrial (EC), ovarian (OC), urinary (UT) and sebaceous tumors (ST). The benefit for universal screening in CRC and EC is well known. However, this benefit in other major lynch-associated tumors is unclear. We performed a systematic review of all published articles in the MEDLINE database between 2005 to 2017 to identify studies performing universal screening for LS in unselected CRC, EC, OC, UT and ST. All cases with MSI-H (instability in two or more markers) or missing one or more proteins on IHC testing were considered screening positive. Cases with MLH1 promoter hypermethylation or BRAF mutation positive were considered to have somatic mutations. A total of 3788 articles were identified in MEDLINE yielding 129 study arms from 113 studies. The overall pooled yield of universal LS screening and germline mismatch gene mutation was significantly different across the major LS-associated tumors (Mann Whitney test, p < 0.001). The pooled screening yield was highest in ST [52.5% (355/676), 95% CI 48.74-56.26%] followed by EC [22.65% (1142/5041), 95% CI 21.54-23.86%], CRC [11.9% (5649/47,545), 95% CI 11.61-12.19%], OC [11.29% (320/2833), 95% CI 10.13-12.47%] and UT [11.2% (31/276), 95% CI 7.48-14.92%]. ST also had the highest pooled germline positivity for mismatch repair gene mutation [18.8%, 33/176, 95%CI 13.03-24.57], followed by EC [2.6% (97/3765), 95% CI 2.09-3.11], CRC [1.8% (682/37,220), 95% CI 1.66-1.94%], UT [1.8%(3/164), 95% CI - 0.24-3.83%] and OC [0.83%(25/2983), 95% CI 0.48-1.12%]. LS screening in EC yielded significantly higher somatic mutations compared to CRC [pooled percentage 16.94% [(538/3176), 95%CI 15.60-18.20%] vs. 5.23% [(1639/26,152), 95% CI 4.93-5.47%], Mann Whitney test, p < 0.0001. Universal LS testing should be routinely performed in OC, UT and STs in addition to CRC and EC. Our findings also support consideration for IHC and somatic mutation testing before germline testing in EC due to higher prevalence of somatic mutations as well as germline testing in all patients with ST. Our results have implications for future design of LS screening programs and further studies are needed to assess the cost effectiveness and burden on genetic counselling services with expanded universal testing for LS.

Prevalence of Lynch syndrome in women with mismatch repair-deficient ovarian cancer

BACKGROUND

There are limited data on the prevalence of Lynch syndrome (LS) in women with primary ovarian cancer with mismatch repair deficiency (MMR-D) by immunohistochemistry (IHC).

MATERIALS AND METHODS

Three hundred and eight cases of primary ovarian, fallopian, and peritoneal cancer between January 2012 and December 2019 were evaluated for MMR-D by IHC. The incidence of LS in this cohort was evaluated.

RESULTS

MMR-D by IHC was identified in 16 of 308 (5.2%) (95% CI: 3.2%-8.3%) primary ovarian-related cancers. Most cases with MMR-D were endometrioid (n = 11, 68.7%); (95% CI: 44.2%-86.1%). MSH2/MSH6 protein loss was detected in eight cases (50.0%); (95% CI: 28.0%-72.0%) and MLH1/PMS2 protein loss was detected in four cases (25.0%); (95% CI: 9.7%-50.0%). MSH6 protein loss was detected in two cases (12.5%); (95% CI: 2.2%-37.3%) and PMS2 protein loss was detected in two cases (12.5%); (95% CI: 2.2%-37.3%). All four cases with MLH1/PMS2 protein loss had MLH1 promotor hypermethylation. All 12 women with ovarian cancer suggestive of LS underwent germline testing and 8 (66.6%); (95% CI: 38.8%-86.5%) were confirmed to have LS.

CONCLUSIONS

Most ovarian cancers with somatic MMR-D were confirmed to have LS in this cohort. Germline testing for LS in addition to BRCA1/2 for all women with an epithelial ovarian cancer would be efficient and would approach 100% sensitivity for identifying Lynch syndrome. Utilization of a multigene panel should also be considered, given the additional non-Lynch germline mutation identified in this cohort.

Management of high, moderate, and low penetrance ovarian cancer susceptibility mutations: an assessment of current risk reduction practices

OBJECTIVE

Limited information exists regarding risk reduction strategies for women with moderate and low penetrance ovarian cancer susceptibility mutations. We sought to assess current risk reduction practice patterns for carriers of these mutations through a survey of members of the Society of Gynecologic Oncology.

METHODS

Society of Gynecologic Oncology members were emailed a survey consisting of two vignettes: (1) a 35-year-old premenopausal woman; (2) a 55-year-old postmenopausal woman with comorbidities. Each vignette contained sub-scenarios in which the patient had either a BRCA1 (relative risk (RR)=30-60), RAD51C (RR=5.0), or ATM (RR=1.5-2.0) mutation. Respondents were queried about their preferred management approach. Summary statistics were performed to describe results of the survey. We used χ² testing for statistical analyses, comparing results according to mutation type and demographic information.

RESULTS

A total of 193 (15%) of 1284 Society of Gynecologic Oncology members responded. For the premenopausal woman, 99%, 80%, and 40% would perform a risk reducing salpingo-oophorectomy prior to menopause in the setting of a BRCA1, RAD51C, and ATM mutation, respectively. For the postmenopausal woman, 98%, 85%, and 42% would proceed with risk reducing salpingo-oophorectomy in the setting of a BRCA1, RAD51C, and ATM mutation, respectively. Response distribution for carriers of RAD51C and ATM mutations were different from BRCA1 in both vignettes (p<0.001).

CONCLUSIONS

Respondents were more likely to perform risk reducing salpingo-oophorectomy, in the setting of a BRCA1, RAD51C, and ATM mutation, earlier and more frequently in the setting of a BRCA1 mutation. However, there was a lack of consensus about management of the moderate and low penetrance mutations, suggesting that more data regarding age specific risks and appropriate risk reduction strategies for these alterations are needed.

Targeted sequencing of genes associated with the mismatch repair pathway in patients with endometrial cancer

Germline variants inactivating the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 cause Lynch syndrome that implies an increased cancer risk, where colon and endometrial cancer are the most frequent. Identification of these pathogenic variants is important to identify endometrial cancer patients with inherited increased risk of new cancers, in order to offer them lifesaving surveillance. However, several other genes are also part of the MMR pathway. It is therefore relevant to search for variants in additional genes that may be associated with cancer risk by including all known genes involved in the MMR pathway. Next-generation sequencing was used to screen 22 genes involved in the MMR pathway in constitutional DNA extracted from full blood from 199 unselected endometrial cancer patients. Bioinformatic pipelines were developed for identification and functional annotation of variants, using several different software tools and custom programs. This facilitated identification of 22 exonic, 4 UTR and 9 intronic variants that could be classified according to pathogenicity. This study has identified several germline variants in genes of the MMR pathway that potentially may be associated with an increased risk for cancer, in particular endometrial cancer, and therefore are relevant for further investigation. We have also developed bioinformatics strategies to analyse targeted sequencing data, including low quality data and genomic regions outside of the protein coding exons of the relevant genes.

Clinicopathological and survival characteristic of mismatch repair status in ovarian clear cell carcinoma

BACKGROUND AND OBJECTIVES

We sought to explore the expression of mismatch repair (MMR) status and its correlation with clinicopathologic and survival characteristics in ovarian clear cell carcinoma (OCCC).

METHODS

Expression of four MMR proteins (MLH1, PMS, MSH2, and MSH6) were measured using tissue microarray-based immunohistochemistry in 120 OCCC patients. The associations of clinicopathologic parameters with recurrence-free survival (RFS) and overall survival (OS) were analyzed by the Kaplan-Meier method, and multivariate analysis was further performed by the Cox regression model.

RESULTS

Overall, 120 OCCC patients met the entry criteria, and their MMR status was detected, consisting of 24 patients with dMMR and 96 patients with proficient MMR (pMMR). Patients with dMMR were strongly associated with platinum-sensitive disease (P = .006) and large tumor volume (P = .038). Among all the patients who have received surgery, tumors with dMMR had a better RFS and OS than those with pMMR (hazard ratio [HR] for recurrence: 0.459 [95% confidence interval {95% CI} = 0.224-0.940], P = .029; HR for death: 0.381 [95% CI = 0.170-0.853], P = .015). In subgroup analysis, dMMR patients experienced a better trend of RFS (HR = 0.273; P = .055) and OS (HR = 0.165; P = .040) than pMMR cases among early stages (I-II), but this difference was not observed in advanced stage (III-IV) patients. Meanwhile, pMMR was associated with a more favorable trend of prognosis than dMMR in platinum-resistant patients (RFS: HR = 0.317, P = .051; OS: HR = 0.370, P = .046). Multivariate analysis revealed that only advanced stages (III-IV) were adverse independent prognosticators for both RFS (HR = 5.938 [95% CI = 2.804-12.574]; P < .001) and OS (HR = 6.209 [95% CI = 2.724-14.156]; P < .001).

CONCLUSION

Tumors with dMMR were related to better OS in OCCC on univariate analysis. Only the tumor stage was an independent prognosticator for both RFS and OS. MMR status is a potentially valuable prognostic index in OCCC patients, and larger prospective studies are required to validate its prognostic role.

Identifying sequence variants contributing to hereditary breast and ovarian cancer in BRCA1 and BRCA2 negative breast and ovarian cancer patients

Families with breast and ovarian cancer are often tested for disease associated sequence variants in BRCA1 and BRCA2. Pathogenic sequence variants (PVs) in these two genes are known to increase breast and ovarian cancer risks in females. However, in most families no PVs are detected in these two genes. Currently, several studies have identified other genes involved in hereditary breast and ovarian cancer (HBOC). To identify genetic risk factors for breast and ovarian cancer in a Norwegian HBOC cohort, 101 breast and/or ovarian cancer patients negative for PVs and variants of unknown clinical significance (VUS) in BRCA1/2 were screened for PVs in 94 genes using next-generation sequencing. Sixteen genes were closely scrutinized. Nine different deleterious germline PVs/likely pathogenic variants (LPVs) were identified in seven genes in 12 patients: three in ATM, and one in CHEK2, ERCC5, FANCM, RAD51C, TP53 and WRN. Additionally, 32 different VUSs were identified and these require further characterization. For carriers of PV/LPV in many of these genes, there are no national clinical management programs in Norway. The diversity of genetic risk factors possibly involved in cancer development show the necessity for more knowledge to improve the clinical follow-up of this genetically diverse patient group.

Incidence of Mismatch Repair Protein Deficiency and Associated Clinicopathologic Features in a Cohort of 104 Ovarian Endometrioid Carcinomas

Patients with Lynch syndrome have up to a 24% risk of developing ovarian carcinoma, but universal mismatch repair (MMR) protein testing of ovarian carcinomas is not standard practice in most institutions. We reviewed 104 unselected ovarian endometrioid carcinomas (OEC) for various clinicopathologic features to determine if any are predictive of MMR loss. Immunohistochemistry for all 4 MMR proteins was performed followed by MLH1 promoter methylation analysis when indicated. Overall, patients had a mean age of 55 years and tumors averaged 12 cm. Most (72%) patients had stage I tumors, 63% were grade 1, and 30% had a synchronous stage IA endometrial endometrioid carcinoma. Peritumoral lymphocytes and intratumoral stromal inflammation were rare, but tumor-infiltrating lymphocytes averaged 47/10 high-power fields. Endometriosis was noted in 71%, adenofibromatous background in 14%, and both in 14% of tumors. Metaplastic changes were common and included squamous metaplasia (63%), clear cell change (32%), mucinous differentiation (24%), and sex cord-like elements (13%). When follow-up was available (n=99), 78% of patients were alive and well, 12% died from disease, 6% died from other causes, and 4% were alive with disease. Unmethylated, MMR-deficient OECs were identified in 7% of the cohort and included MSH2/MSH6 (n=4), MSH6 (n=2), and PMS2 (n=1). All these tumors were stage I, 71% grade 1, and 57% had a synchronous endometrial endometrioid carcinoma. Among patients in this group with follow-up (n=5), all were alive without evidence of disease (mean 150 mo). Given that no clinicopathologic features were associated with MMR deficiency on univariate analysis, this study highlights the importance of universal MMR screening in OECs.

Current Position of the Molecular Therapeutic Targets for Ovarian Clear Cell Carcinoma: A Literature Review

Ovarian clear cell carcinoma (OCCC) shows low sensitivity to conventional chemotherapy and has a poor prognosis, especially in advanced stages. Therefore, the development of innovative therapeutic strategies and precision medicine for the treatment of OCCC are important. Recently, several new molecular targets have been identified for OCCC, which can be broadly divided into four categories: (a) downstream pathways of receptor tyrosine kinases, (b) anti-oxidative stress molecules, (c) AT-rich interactive domain 1A-related chromatin remodeling errors, and (d) anti-programmed death ligand 1/programmed cell death 1 agents. Several inhibitors have been discovered for these targets, and the suppression of OCCC cells has been demonstrated both in vitro and in vivo. However, no single inhibitor has shown a sufficient effectiveness in clinical pilot studies. This review outlines recent progress regarding the molecular biological characteristics of OCCC to identify future directions for the development of precision medicine and combinatorial therapies to treat OCCC.

Lynch Syndrome: From Screening to Diagnosis to Treatment in the Era of Modern Molecular Oncology

Lynch syndrome is a hereditary cancer predisposition syndrome caused by germline alterations in the mismatch repair genes and is the most common etiology of hereditary colorectal cancer. While Lynch syndrome was initially defined by the clinical Amsterdam criteria, these criteria lack the sensitivity needed for clinical utility. This review covers the evolution of screening for Lynch syndrome from the use of tumor microsatellite instability and/or somatic alterations in mismatch repair protein expression by immunohistochemistry to the newest methods using next-generation sequencing. Additionally, it discusses the clinical implications of the diagnosis of Lynch syndrome as it affects cancer therapeutics and the role of screening in noncolorectal Lynch-associated cancers. As molecular oncology continues to evolve, it is crucial to remain current on the increasing complexity of Lynch syndrome diagnostics and treatment options.

[Epidemiology of microsatellite instability across solid neoplasms]

Microsatellite instability (MSI) is a predictive biomarker for the efficacy of immune checkpoint inhibitors, regardless of the tumor type. While clinical characteristics of MSI cancer patients have been largely described in tumor localizations frequently associated with this genetic phenotype (i.e. colorectal cancer, endometrial cancer), it remains poorly characterized in other neoplasms. Pan-tumor high-throughput genome sequence analyses have contributed to the broadening of knowledge about the landscape of MSI. This review aims at synthetizing the literature concerning the frequency of MSI status in solid cancers, according to the cancer stage and the hereditary or sporadic origin of the mismatch repair deficiency. We then check for other cancers frequently associated with MSI and describe the clinical and pathological characteristics that should suggest a MSI phenotype.

Familial risks of ovarian cancer by age at diagnosis, proband type and histology

Ovarian cancer is a heterogeneous disease. Data regarding familial risks for specific proband, age at diagnosis and histology are limited. Such data can assist genetic counseling and help elucidate etiologic differences among various histologic types of ovarian malignancies. By using the Swedish Family-Cancer Database, we calculated relative risks (RRs) for detailed family histories using a two-way comparison, which implied e.g. estimation of RRs for overall ovarian cancer when family history was histology-specific ovarian cancer, and conversely, RRs for histology-specific ovarian cancer when family history was overall ovarian cancer. In families of only mother, only sisters or both mother and sisters diagnosed with ovarian cancer, cancer risks for ovary were 2.40, 2.59 and 10.40, respectively; and were higher for cases diagnosed before the age of 50 years. All histological types showed a familial risk in two-way analyses, except mucinous and sex cord-stromal tumors. RRs for concordant histology were found for serous (2.47), endometrioid (3.59) and mucinous ovarian cancers (6.91). Concordant familial risks were highest for mucinous cancer; for others, some discordant associations, such as endometrioid-undifferentiated (9.27) and serous-undifferentiated (4.80), showed the highest RRs. Familial risks are high for early-onset patients and for those with multiple affected relatives. Sharing of different histological types of ovarian cancer is likely an indication of the complexity of the underlying mechanisms.

Familial Ovarian Cancer Clusters with Other Cancers

Familial risk of ovarian cancer is well-established but whether ovarian cancer clusters with other cancers and the clusters differ by histology remains uncertain. Using data from the Swedish Family-Cancer Database, we explored familial associations of ovarian cancer with other cancers with a novel approach; relative risk for (histology-specific) ovarian cancer was estimated in families with patients affected by other cancers, and conversely, risks for other cancers in families with (histology-specific) ovarian cancer patients. Eight discordant cancers were associated with ovarian cancer risk, of which family history of breast cancer showed a dose-response (P-trend <0.0001). Conversely, risks of eight types of cancer increased in families with ovarian cancer patients, and dose-responses were shown for risks of liver (P-trend = 0.0083) and breast cancers (P-trend <0.0001) and cancer of unknown primary (P-trend = 0.0157). Some cancers were only associated with histology-specific ovarian cancers, e.g. endometrial cancer was only associated with endometrioid type but with highest significance. Novel associations with virus-linked cancers of the nose and male and female genitals were found. The results suggest that ovarian cancer shares susceptibility with a number of other cancers. This might alert genetic counselors and challenge approaches for gene and gene-environment identification.

Predictors of next-generation sequencing panel selection using a shared decision-making approach

The introduction of next-generation sequencing panels has transformed the approach for genetic testing in cancer patients, however, established guidelines for their use are lacking. A shared decision-making approach has been adopted by our service, where patients play an active role in panel selection and we sought to identify factors associated with panel selection and report testing outcomes. Demographic and clinical data were gathered for female breast and/or ovarian cancer patients aged 21 and over who underwent panel testing. Panel type was classified as ‘breast cancer panel’ (BCP) or ‘multi-cancer panel’ (MCP). Stepwise multiple logistic regression analysis was used to identify clinical factors most predictive of panel selection. Of the 265 included subjects, the vast majority selected a broader MCP (81.5%). Subjects who chose MCPs were significantly more likely to be ≥50 years of age (49 vs. 31%; p < 0.05), Chinese (76 vs. 47%; p < 0.001) and have a personal history of ovarian cancer (41 vs. 8%; p < 0.001) with the latter two identified as the best predictors of panel selection. Family history of cancer was not significantly associated with panel selection. There were no statistically significant differences in result outcomes between the two groups. In summary, our findings demonstrate that the majority of patients have a preference for interrogating a larger number of genes beyond those with established testing guidelines, despite the additional likelihood of uncertainty. Individual factors, including cancer history and ethnicity, are the best predictors of panel selection.

Thanks to next-generation sequencing (NGS) it is possible to test multiple genes for cancer susceptibility quickly and cheaply. At the National Cancer Centre Singapore, shared decision-making is used to actively encourage the involvement of patients in the selection of either a ‘breast cancer panel’ (BCP) or a broader ‘multi-cancer panel’ (MCP) test. Joanne Ngeow at the Centre’s Cancer Genetics Service and colleagues examined the choices made by 265 patients with breast and/or ovarian cancer following detailed pre-test counselling by the genetics team. The majority of patients selected the MCP, potentially highlighting a willingness to accept the additional uncertainty that comes with broader NGS panels. Interestingly, a personal history of ovarian cancer and Chinese ethnicity, but not a family history of cancer, were significantly associated with panel selection.

Correlation between germline mutations in MMR genes and microsatellite instability in ovarian cancer specimens

A high proportion of ovarian cancers from women who carry germline mutations in mismatch repair (MMR) genes demonstrate microsatellite instability (MSI). The utility of pre-screening ovarian cancer specimens for MSI to identify potential patients for germline screening for MMR mutations is uncertain. 656 women with malignant ovarian cancer underwent both MSI testing and germline mutation testing for large rearrangements in three MMR genes, MLH1, MSH2 and MSH6. Germline DNA sequencing data for the same genes was available. Among the 656 women, only four (0.6%) carried a clearly pathogenic MMR mutation. All four cancers from patients with mutations had loss of two or more microsatellite markers (MSI-high). Eighty-four of 652 (13.0%) women without a mutation had MSI-high ovarian cancers. Using MSI-high as a prescreening criterion, the sensitivity of MSI testing to identify germline MMR gene mutations was 100% and the positive predictive value was 4.5%. Germline mutations in MLH1, MSH2 and MSH6 are rare among unselected cases of ovarian cancer. Patients with germline mutations often will have MSI-positive cancers and pre-screening of ovarian cancer specimens may be an efficient way of identifying patients with Lynch syndrome.

Genetic epidemiology of ovarian cancer and prospects for polygenic risk prediction

Epithelial ovarian cancer (EOC) is a heterogeneous disease with a major heritable component. The different histotypes of invasive disease - high grade serous, clear cell, endometrioid and mucinous - are associated with different underlying genetic susceptibility and epidemiological and lifestyle risk factors, all of which contribute to the different biology and clinical characteristics of each histotype. A combination of familial and population based sequencing studies, and genome wide association studies (GWAS) have identified a range of genetic susceptibility alleles for EOC comprising rare but highly penetrant genes (e.g. BRCA1, BRCA2) that are responsible for familial clustering of ovarian cancer cases; more moderate penetrance susceptibility genes (e.g. BRIP1, RAD51C/D, MSH6); and multiple common but low penetrance susceptibility alleles identified by GWAS. Identifying genetic risk alleles for ovarian cancer has had a significant impact on disease prevention strategies; for example it is now routine clinical practice for individuals with germline BRCA1 and BRCA2 mutations to undergo risk reducing salpingo-oophorectomy. Because ovarian cancers are commonly diagnosed at a late clinical stage when the prognosis is poor, the continued development of genetic risk prediction and prevention strategies will represent an important approach to reduce mortality due to ovarian cancer. Advances in genomics technologies that enable more high-throughput genetic testing, combined with research studies that identify additional EOC risk alleles will likely provide further opportunities to establish polygenic risk prediction approaches, based on combinations of rare high/moderate penetrance susceptibility genes and common, low penetrance susceptibility alleles. This article reviews the current literature describing the genetic and epidemiological components of ovarian cancer risk, and discusses both the opportunities and challenges in using this information for clinical risk prediction and prevention.

Epidemiology of ovarian cancer: a review

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

Epidemiology of ovarian cancer: a review

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

Epidemiology of ovarian cancer: a review

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

Revisiting breast cancer patients who previously tested negative for BRCA mutations using a 12-gene panel

PURPOSE

BRCA mutations contribute to about 20% of all hereditary breast cancers. With full-genome sequencing as the emerging standard for genetic testing, other breast cancer susceptibility genes have been identified and may collectively contribute to up to 30% of all hereditary breast cancers. We re-assessed women who had previously tested negative for a BRCA mutation when outdated techniques were used, and discuss the implications of identifying a mutation several years after initial genetic testing.

METHODS

We evaluated the prevalence of mutations in 12 breast cancer susceptibility genes (including BRCA1 and BRCA2) in 190 breast cancer patients with a strong family history of breast cancer. These women had previously tested negative for mutations in the large coding exons of BRCA1 and BRCA2 using the protein truncation test (PTT) between the years of 1996 and 2013.

RESULTS

We identified pathogenic mutations in 17 of 190 (9%) women. Six mutations were detected in BRCA1 (n = 2) and BRCA2 (n = 4). Eleven mutations were found in other breast cancer susceptibility genes including CHEK2 (n = 5), PALB2 (n = 2), BLM (n = 2), ATM (n = 1) and TP53 (n = 1).

CONCLUSION

Among 190 breast cancer patients with a family history of the disease, and who previously received a negative result for BRCA mutations using the PTT, 17 (9%) women were found to carry a high-risk pathogenic mutation in a breast cancer susceptibility gene. Six of these women were BRCA mutation carriers who were missed previously. These findings support the rationale for updated genetic testing in patients who tested BRCA mutation negative using outdated techniques.

Inherited Mutations in Women With Ovarian Carcinoma

IMPORTANCE

Germline mutations in BRCA1 and BRCA2 are relatively common in women with ovarian, fallopian tube, and peritoneal carcinoma (OC) causing a greatly increased lifetime risk of these cancers, but the frequency and relevance of inherited mutations in other genes is less well characterized.

OBJECTIVE

To determine the frequency and importance of germline mutations in cancer-associated genes in OC.

DESIGN, SETTING, AND PARTICIPANTS

A study population of 1915 woman with OC and available germline DNA were identified from the University of Washington (UW) gynecologic tissue bank (n = 570) and from Gynecologic Oncology Group (GOG) phase III clinical trials 218 (n = 788) and 262 (n = 557). Patients were enrolled at diagnosis and were not selected for age or family history. Germline DNA was sequenced from women with OC using a targeted capture and multiplex sequencing assay.

MAIN OUTCOMES AND MEASURES

Mutation frequencies in OC were compared with the National Heart, Lung, and Blood Institute GO Exome Sequencing Project (ESP) and the Exome Aggregation Consortium (ExAC). Clinical characteristics and survival were assessed by mutation status.

RESULTS

Overall, the median (range) age at diagnosis was 60 (28-91) years in patients recruited from UW and 61 (23-87) years in patients recruited from the GOG trials. A higher number of black women were recruited from the GOG trials (4.3% vs 1.4%; P = .009); but in patients recruited from UW, there was a higher proportion of fallopian tube carcinomas (13.3% vs 5.7%; P < .001); stage I and II disease (14.6% vs 0% [GOG trials were restricted to advanced-stage cancer]); and nonserous carcinomas (29.9% vs 13.1%, P < .001). Of 1915 patients, 280 (15%) had mutations in BRCA1 (n = 182), or BRCA2 (n = 98), and 8 (0.4%) had mutations in DNA mismatch repair genes. Mutations in BRIP1 (n = 26), RAD51C (n = 11), RAD51D (n = 11), PALB2 (n = 12), and BARD1 (n = 4) were significantly more common in patients with OC than in the ESP or ExAC, present in 3.3%. Race, histologic subtype, and disease site were not predictive of mutation frequency. Patients with a BRCA2 mutation from the GOG trials had longer progression-free survival (hazard ratio [HR], 0.60; 95% CI, 0.45-0.79; P < .001) and overall survival (HR, 0.39; 95% CI, 0.25-0.60; P < .001) compared with those without mutations.

CONCLUSIONS AND RELEVANCE

Of 1915 patients with OC, 347 (18%) carried pathogenic germline mutations in genes associated with OC risk. PALB2 and BARD1 are suspected OC genes and together with established OC genes (BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, MSH2, MLH1, PMS2, and MSH6) bring the total number of genes suspected to cause hereditary OC to 11.

Prevalence of Lynch syndrome in unselected patients with endometrial or ovarian cancer

INTRODUCTION

Lynch syndrome is known by healthcare providers mainly for patients with colorectal cancer. Awareness of other associated tumors, such as endometrial or ovarian cancer, is low. This study aimed to analyze the prevalence of Lynch syndrome in unselected patients with endometrial or ovarian cancer. In addition, the willingness of patients and family members to undergo germline mutation testing was investigated.

METHODS

The medical records of all patients diagnosed with endometrial or ovarian cancer at the Department of Gynecology and Obsterics, University Hospital Dresden, between 1998 and 2012, were screened for a family history of HNPCC-associated cancer. Telephone interviews were used to screen, inform, and enroll patients in this genetic analysis study. Molecular analysis was performed by prescreening of tumor tissue, followed by germline mutation analysis.

RESULTS

Two hundred and eighty-three patients were diagnosed with endometrial cancer, 291 with ovarian cancer, and 14 with both. A positive family history for tumors associated with Lynch syndrome was documented for 61 patients. Two pathogenic mutations in the genes MLH1 and MSH2 in nine genetic analyses had already been detected before. After genetic counseling, only 10 of 31 index patients (32.3 %) consented for mutation analysis. However, no additional pathogenic heterozygous mutations were found.

CONCLUSION

In this retrospective cohort study in unselected patients with endometrial or ovarian cancer, only a small number of patients with suspected Lynch syndrome could be identified. Of those, acceptance of germline analyses was moderate, only. As a result, the rate of identified pathogenic germline mutations was lower than expected. Therefore, we are convinced that more information on cancer risks, options for predictive molecular testing and preventive procedures, needs to be provided to patients and gynecologists.

Mismatch Repair Deficiency and Response to Immune Checkpoint Blockade

: More than 1.6 million new cases of cancer will be diagnosed in the U.S. in 2016, resulting in more than 500,000 deaths. Although chemotherapy has been the mainstay of treatment in advanced cancers, immunotherapy development, particularly with PD-1 inhibitors, has changed the face of treatment for a number of tumor types. One example is the subset of tumors characterized by mismatch repair deficiency and microsatellite instability that are highly sensitive to PD-1 blockade. Hereditary forms of cancer have been noted for more than a century, but the molecular changes underlying mismatch repair-deficient tumors and subsequent microsatellite unstable tumors was not known until the early 1990s. In this review article, we discuss the history and pathophysiology of mismatch repair, the process of testing for mismatch repair deficiency and microsatellite instability, and the role of immunotherapy in this subset of cancers.

IMPLICATIONS FOR PRACTICE

Mismatch repair deficiency has contributed to our understanding of carcinogenesis for the past 2 decades and now identifies a subgroup of traditionally chemotherapy-insensitive solid tumors as sensitive to PD-1 blockade. This article seeks to educate oncologists regarding the nature of mismatch repair deficiency, its impact in multiple tumor types, and its implications for predicting the responsiveness of solid tumors to immune checkpoint blockade.

Mismatch Repair Deficiency and Response to Immune Checkpoint Blockade

: More than 1.6 million new cases of cancer will be diagnosed in the U.S. in 2016, resulting in more than 500,000 deaths. Although chemotherapy has been the mainstay of treatment in advanced cancers, immunotherapy development, particularly with PD-1 inhibitors, has changed the face of treatment for a number of tumor types. One example is the subset of tumors characterized by mismatch repair deficiency and microsatellite instability that are highly sensitive to PD-1 blockade. Hereditary forms of cancer have been noted for more than a century, but the molecular changes underlying mismatch repair-deficient tumors and subsequent microsatellite unstable tumors was not known until the early 1990s. In this review article, we discuss the history and pathophysiology of mismatch repair, the process of testing for mismatch repair deficiency and microsatellite instability, and the role of immunotherapy in this subset of cancers.

IMPLICATIONS FOR PRACTICE

Mismatch repair deficiency has contributed to our understanding of carcinogenesis for the past 2 decades and now identifies a subgroup of traditionally chemotherapy-insensitive solid tumors as sensitive to PD-1 blockade. This article seeks to educate oncologists regarding the nature of mismatch repair deficiency, its impact in multiple tumor types, and its implications for predicting the responsiveness of solid tumors to immune checkpoint blockade.

Genetic evaluation and testing for hereditary forms of cancer in the era of next-generation sequencing

The introduction of next-generation sequencing (NGS) technology in testing for hereditary cancer susceptibility allows testing of multiple cancer susceptibility genes simultaneously. While there are many potential benefits to utilizing this technology in the hereditary cancer clinic, including efficiency of time and cost, there are also important limitations that must be considered. The best panel for the given clinical situation should be selected to minimize the number of variants of unknown significance. The inclusion in panels of low penetrance or newly identified genes without specific actionability can be problematic for interpretation. Genetic counselors are an essential part of the hereditary cancer risk assessment team, helping the medical team select the most appropriate test and interpret the often complex results. Genetic counselors obtain an extended family history, counsel patients on the available tests and the potential implications of results for themselves and their family members (pre-test counseling), explain to patients the implications of the test results (post-test counseling), and assist in testing family members at risk.

Inherited Mutations in Women With Ovarian Carcinoma

IMPORTANCE

Germline mutations in BRCA1 and BRCA2 are relatively common in women with ovarian, fallopian tube, and peritoneal carcinoma (OC) causing a greatly increased lifetime risk of these cancers, but the frequency and relevance of inherited mutations in other genes is less well characterized.

OBJECTIVE

To determine the frequency and importance of germline mutations in cancer-associated genes in OC.

DESIGN, SETTING, AND PARTICIPANTS

A study population of 1915 woman with OC and available germline DNA were identified from the University of Washington (UW) gynecologic tissue bank (n = 570) and from Gynecologic Oncology Group (GOG) phase III clinical trials 218 (n = 788) and 262 (n = 557). Patients were enrolled at diagnosis and were not selected for age or family history. Germline DNA was sequenced from women with OC using a targeted capture and multiplex sequencing assay.

MAIN OUTCOMES AND MEASURES

Mutation frequencies in OC were compared with the National Heart, Lung, and Blood Institute GO Exome Sequencing Project (ESP) and the Exome Aggregation Consortium (ExAC). Clinical characteristics and survival were assessed by mutation status.

RESULTS

Overall, the median (range) age at diagnosis was 60 (28-91) years in patients recruited from UW and 61 (23-87) years in patients recruited from the GOG trials. A higher number of black women were recruited from the GOG trials (4.3% vs 1.4%; P = .009); but in patients recruited from UW, there was a higher proportion of fallopian tube carcinomas (13.3% vs 5.7%; P < .001); stage I and II disease (14.6% vs 0% [GOG trials were restricted to advanced-stage cancer]); and nonserous carcinomas (29.9% vs 13.1%, P < .001). Of 1915 patients, 280 (15%) had mutations in BRCA1 (n = 182), or BRCA2 (n = 98), and 8 (0.4%) had mutations in DNA mismatch repair genes. Mutations in BRIP1 (n = 26), RAD51C (n = 11), RAD51D (n = 11), PALB2 (n = 12), and BARD1 (n = 4) were significantly more common in patients with OC than in the ESP or ExAC, present in 3.3%. Race, histologic subtype, and disease site were not predictive of mutation frequency. Patients with a BRCA2 mutation from the GOG trials had longer progression-free survival (hazard ratio [HR], 0.60; 95% CI, 0.45-0.79; P < .001) and overall survival (HR, 0.39; 95% CI, 0.25-0.60; P < .001) compared with those without mutations.

CONCLUSIONS AND RELEVANCE

Of 1915 patients with OC, 347 (18%) carried pathogenic germline mutations in genes associated with OC risk. PALB2 and BARD1 are suspected OC genes and together with established OC genes (BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, MSH2, MLH1, PMS2, and MSH6) bring the total number of genes suspected to cause hereditary OC to 11.

Genetic characterization of early onset ovarian carcinoma

OBJECTIVE

Ovarian carcinoma (OC) is rare in young women and the fraction of early onset OC attributable to inherited mutations in known OC genes is uncertain. We sought to characterize the fraction of OC that is heritable in women diagnosed with ovarian, fallopian tube, or peritoneal carcinoma at forty years of age or younger.

METHODS

We sequenced germline DNA from forty-seven women diagnosed with OC at age 40 or younger ascertained through a gynecologic oncology tissue bank or referred from outside providers using BROCA, a targeted capture and massively parallel sequencing platform that can detect all mutation classes. We evaluated 11 genes associated with ovarian carcinoma (BARD1, BRCA1, BRCA2, BRIP1, MLH1, MSH2, MSH6, PALB2, PMS2, RAD51D, and RAD51C) and additional candidate genes in DNA repair (ATM, BAP1, CHEK2, MRE11A, NBN, PTEN, TP53). We counted only clearly damaging mutations.

RESULTS

Damaging mutations in OC genes were identified in 13 of 47 (28%) subjects, of which 10 (77%) occurred in BRCA1 and one each occurred in BRCA2, MSH2, and RAD51D. Women with a strong family history were no more likely to have an OC gene mutation (8/17, 47%) than those without a strong family history (9/30, 30%, P=0.35). Additionally, damaging mutations in non-OC genes were identified, one in NBN and one in CHEK2.

CONCLUSIONS

A high proportion of young women with invasive OC have mutations in BRCA1, and a smaller fraction have mutations in other known OC genes. Family history was not associated with mutation status in these early onset cases.