Prevalence of pathogenic germline variants detected by multigene sequencing in unselected Japanese patients with ovarian cancer

Targeted DNA sequencing of high-grade serous ovarian carcinoma reveals association of TP53 mutations with platinum resistance when combined with gene expression

High-grade serous ovarian carcinoma (HGSC) is the most common subtype of ovarian cancer and is among the most fatal gynecological malignancies worldwide, due to late diagnosis at advanced stages and frequent therapy resistance. In 47 HGSC patients, we assessed somatic and germline genetic variability of a custom panel of 144 known or suspected HGSC-related genes by high-coverage targeted DNA sequencing to identify the genetic determinants associated with resistance to platinum-based therapy. In the germline, the most mutated genes were DNAH14 (17%), RAD51B (17%), CFTR (13%), BRCA1 (11%), and RAD51 (11%). Somatically, the most mutated gene was TP53 (98%), followed by CSMD1/2/3 (19/19/36%), and CFTR (23%). Results were compared with those from whole exome sequencing of a similar set of 35 HGSC patients. Somatic variants in TP53 were also validated using GENIE data of 1287 HGSC samples. Our approach showed increased prevalence of high impact somatic and germline mutations, especially those affecting splice sites of TP53, compared to validation datasets. Furthermore, nonsense TP53 somatic mutations were negatively associated with patient survival. Elevated TP53 transcript levels were associated with platinum resistance and presence of TP53 missense mutations, while decreased TP53 levels were found in tumors carrying mutations with predicted high impact, which was confirmed in The Cancer Genome Atlas data (n = 260). Targeted DNA sequencing of TP53 combined with transcript quantification may contribute to the concept of precision oncology of HGSC. Future studies should explore targeting the p53 pathway based on specific mutation types and co-analyze the expression and mutational profiles of other key cancer genes.

Functional analysis of MMR gene VUS from potential Lynch syndrome patients

Lynch syndrome is caused by inactivating variants in DNA mismatch repair genes, namely MLH1, MSH2, MSH6 and PMS2. We have investigated five MLH1 and one MSH2 variants that we have identified in Turkish and Tunisian colorectal cancer patients. These variants comprised two small deletions causing frameshifts resulting in premature stops which could be classified pathogenic (MLH1 p.(His727Profs*57) and MSH2 p.(Thr788Asnfs*11)), but also two missense variants (MLH1 p.(Asn338Ser) and p.(Gly181Ser)) and two small, in-frame deletion variants (p.(Val647-Leu650del) and p.(Lys678_Cys680del)). For such small coding genetic variants, it is unclear if they are inactivating or not. We here provide clinical description of the variant carriers and their families, and we performed biochemical laboratory testing on the variant proteins to test if their stability or their MMR activity are compromised. Subsequently, we compared the results to in-silico predictions on structure and conservation. We demonstrate that neither missense alteration affected function, while both deletion variants caused a dramatic instability of the MLH1 protein, resulting in MMR deficiency. These results were consistent with the structural analyses that were performed. The study shows that knowledge of protein function may provide molecular explanations of results obtained with functional biochemical testing and can thereby, in conjunction with clinical information, elevate the evidential value and facilitate clinical management in affected families.

Germline Mutational Landscape and Novel Targetable RAD51D Variant in Chinese Patients With Ovarian Cancer

PURPOSE

Genetic variants of ovarian cancer (OV) show ethnic differences, but data from the Chinese population are still insufficient. Here, we elucidate the inheritance landscape in Chinese patients with OV and examine the functional implications of a Chinese-enriched RAD51D variant.

METHODS

Between 2015 and 2018, 373 consecutive patients with OV were prospectively enrolled. Variants of BRCA1/2, other homologous recombination repair (HRR) genes, and DNA mismatch repair (MMR) genes were analyzed using next-generation sequencing. An enriched RAD51D variant was identified, and its functional effects were examined using Cell Counting Kit-8, colony formation, transwell migration, and drug sensitivity assays.

RESULTS

Overall, 31.1% (116/373) of patients had at least one pathogenic or likely pathogenic germline variant. BRCA1 and BRCA2 accounted for 16.09% and 5.36%, respectively, with one patient having both variants. In addition, 32 (8.58%) patients carried other HRR gene variants, whereas three (0.8%) patients had MMR gene variants. The RAD51D variant ranked third (8/373, 2.1%), and its rate was much higher than that in other populations. Remarkably, all eight patients harbored the RAD51D K91fs variant (c.270_271dup, p.Lys91Ilefs*13) and demonstrated satisfactory platinum response and favorable prognosis. This variant confers enhanced sensitivity to poly (ADP-ribose) polymerase inhibitors in OV cells. However, the effects on platinum sensitivity were inconsistent across different cell lines. Against the background of the TP53 variant, RAD51D K91fs variant showed increased sensitivity to cisplatin.

CONCLUSION

Our study revealed the inheritance landscape of OV and identified an enriched RAD51D variant in Chinese patients with OV. This can serve as an important reference for OV management and a potential therapeutic target.

Therapeutic applications of germline testing for cancer predisposition genes in Asia in the real world

BACKGROUND

Germline genetic testing is traditionally carried out in patients suspected with hereditary cancer syndrome for enhanced cancer surveillance and/or preventive strategies, but is increasingly carried out for therapeutic indications.

MATERIALS AND METHODS

We conducted a retrospective review of patients who underwent germline genetic testing at our centre to determine the prevalence of actionable pathogenic germline variants (PGV) and their clinical utility.

RESULTS

From 2000 to 2022, 1154 cancer patients underwent germline testing, with the majority (945/1154) tested with multi-gene panels. Four hundred and eleven (35.6%) patients harboured a PGV and 334 (81%) were clinically actionable. BRCA1/2 accounted for 62.3% of actionable mutations, followed by mismatch repair (18%), and other homologous recombination repair (HRR) genes (19.7%). One hundred and fifty-two germline-positive patients have advanced cancers, and 79 received germline-directed therapies (poly ADP ribose polymerase inhibitors = 75; immunotherapy = 4). Median duration of immunotherapy and poly ADP ribose polymerase were 20.5 months (range 5-40 months) and 8 months (range 1-76 months), respectively. Among BRCA/HRR mutation carriers who received platinum-based chemotherapy, pathological complete response rate in the neoadjuvant setting was 53% (n = 17 breast cancers) and objective response rate was >80% in the advanced setting (n = 71).

CONCLUSIONS

One-third of cancer patients tested carried a PGV and ∼80% were clinically actionable. Three-quarters of germline-positive advanced cancer patients received germline-directed therapies in the real world, underscoring the practical utility of germline testing to guide cancer therapeutics.

Risk-reducing decisions regarding germline BRCA pathogenic variant: focusing on the timing of genetic testing and RRSO

BACKGROUND

In Japan, the public insurance policy was revised in 2020 to cover hereditary breast and ovarian cancer (HBOC), including genetic testing and surveillance, for patients with breast cancer (BC). Consequently, the demand for risk-reducing salpingo-oophorectomy (RRSO) has increased. This study aimed to clarify the changes in the demand and timing of genetic testing and RRSO associated with public insurance coverage for HBOC in Japan.

METHODS

This retrospective analysis included 350 women with germline BRCA (gBRCA) pathogenic variants (PVs) who had visited gynaecologists; they received gBRCA genetic testing at 45.1±10.6 (20-74) years. The use of medical testing and preventive treatment was compared between the preinsurance and postinsurance groups using Mann-Whitney U and Fisher's exact tests.

RESULTS

The findings indicate that RRSO rates doubled from 31.4% to 62.6% among patients with gBRCA-PV. The implementation rate was 32.4% among unaffected carriers and 70.3% among BC-affected patients. Younger patients received genetic testing with significantly shorter intervals between BC diagnosis and genetic testing and between genetic testing and RRSO.

CONCLUSION

Overall, the insurance coverage for HBOC patients with BC has increased the frequency of RRSO in Japan. However, a comparison between the number of probands and family members indicated that the diagnosis among family members is inadequate. The inequality in the use of genetic services by socioeconomic groups is an issue of further concern.

Landscape of somatic mutated genes and inherited susceptibility genes in gynecological cancer

Traditionally, gynecological cancers have been classified based on histology. Since remarkable advancements in next-generation sequencing technology have enabled the exploration of somatic mutations in various cancer types, comprehensive sequencing efforts have revealed the genomic landscapes of some common forms of human cancer. The genomic features of various gynecological malignancies have been reported by several studies of large-scale genomic cohorts, including The Cancer Genome Atlas. Although recent comprehensive genomic profiling tests, which can detect hundreds of genetic mutations at a time from cancer tissues or blood samples, have been increasingly used as diagnostic clinical biomarkers and in therapeutic management decisions, germline pathogenic variants associated with hereditary cancers can also be detected using this test. Gynecological cancers are closely related to genetic factors, with approximately 5% of endometrial cancer cases and 20% of ovarian cancer cases being caused by germline pathogenic variants. Hereditary breast and ovarian cancer syndrome and Lynch syndrome are the two major cancer susceptibility syndromes among gynecological cancers. In addition, several other hereditary syndromes have been reported to be associated with gynecological cancers. In this review, we highlight the genes for somatic mutation and germline pathogenic variants commonly seen in gynecological cancers. We first describe the relationship between clinicopathological attributes and somatic mutated genes. Subsequently, we discuss the characteristics and clinical management of inherited cancer syndromes resulting from pathogenic germline variants in gynecological malignancies.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of immunotherapy in patients with DNA mismatch repair deficient (dMMR) tumors, third edition

BACKGROUND

Clinical trials have reported the efficacy of immune checkpoint inhibitors in the treatment of mismatch repair-deficient (dMMR) advanced solid tumors. The accumulated evidence of tumor agnostic agent has been made since PD-1 inhibitor was approved and used in clinical practice. Therefore, we have revised the guideline "Japan Society of Clinical Oncology provisional clinical opinion for the diagnosis and use of immunotherapy in patients with deficient DNA mismatch repair tumors, cooperated by Japanese Society of Medical Oncology, First Edition".

METHODS

Clinical questions regarding medical care were formulated for patients with dMMR advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by Japan Society of Clinical Oncology (JSCO), Japanese Society of Medical Oncology (JSMO), and Japanese society of pediatric hematology/oncology (JSPHO) voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO and the public comments among all societies' members were done.

RESULTS

The current guideline describes two clinical questions and eight recommendations for whom, when, and how MMR status should be tested.

CONCLUSION

In this guideline, the committee proposed eight recommendations for performing MMR testing properly to select patients who are likely to benefit from immunotherapy.

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.

Genetic analyses of DNA repair pathway associated genes implicate new candidate cancer predisposing genes in ancestrally defined ovarian cancer cases

Not all familial ovarian cancer (OC) cases are explained by pathogenic germline variants in known risk genes. A candidate gene approach involving DNA repair pathway genes was applied to identify rare recurring pathogenic variants in familial OC cases not associated with known OC risk genes from a population exhibiting genetic drift. Whole exome sequencing (WES) data of 15 OC cases from 13 families tested negative for pathogenic variants in known OC risk genes were investigated for candidate variants in 468 DNA repair pathway genes. Filtering and prioritization criteria were applied to WES data to select top candidates for further analyses. Candidates were genotyped in ancestry defined study groups of 214 familial and 998 sporadic OC or breast cancer (BC) cases and 1025 population-matched controls and screened for additional carriers in 605 population-matched OC cases. The candidate genes were also analyzed in WES data from 937 familial or sporadic OC cases of diverse ancestries. Top candidate variants in ERCC5, EXO1, FANCC, NEIL1 and NTHL1 were identified in 5/13 (39%) OC families. Collectively, candidate variants were identified in 7/435 (1.6%) sporadic OC cases and 1/566 (0.2%) sporadic BC cases versus 1/1025 (0.1%) controls. Additional carriers were identified in 6/605 (0.9%) OC cases. Tumour DNA from ERCC5, NEIL1 and NTHL1 variant carriers exhibited loss of the wild-type allele. Carriers of various candidate variants in these genes were identified in 31/937 (3.3%) OC cases of diverse ancestries versus 0-0.004% in cancer-free controls. The strategy of applying a candidate gene approach in a population exhibiting genetic drift identified new candidate OC predisposition variants in DNA repair pathway genes.

Comprehensive Analysis of Adverse Events Induced by PARP Inhibitors Using JADER and Time to Onset

Poly (ADP-ribose) polymerase (PARP) inhibitors are effective against breast cancer susceptibility gene (BRCA) mutations. Clinical trials have reported hematologic toxicity and gastrointestinal symptoms as class effects of PARP inhibitors. However, information on adverse events (AEs) in a Japanese clinical cohort is currently lacking. In this study, we conducted a comprehensive survey of the AEs of two PARP inhibitors, olaparib and niraparib, using the Japanese Adverse Reaction Reporting (JADER) database provided by the Pharmaceuticals and Medical Devices Agency (PMDA). Moreover, we also analyzed the course and time to the onset of AEs. Signals were detected for 15 and 11 AEs for olaparib and niraparib, respectively. Most occurred within the first month of treatment with either agent. These results may indicate the importance of early response and monitoring after beginning PARP inhibitor therapy. The results of this study may be useful for managing side effects and suggesting supportive care for patients using PARP inhibitors in the future.

Current Status of Hereditary Breast and Ovarian Cancer Practice Among Gynecologic Oncologists in Japan: A Nationwide Survey by the Japan Society of Gynecologic Oncology (JSGO)

Objective

The practices pertaining to hereditary breast and ovarian cancer (HBOC) in Japan have been rapidly changing owing to the clinical development of poly(ADP-ribose) polymerase inhibitors, the increasing availability of companion diagnostics, and the broadened insurance coverage of HBOC management from April 2020. A questionnaire of gynecologic oncologists was conducted to understand the current status and to promote the widespread standardization of future HBOC management.

Methods

A Google Form questionnaire was administered to the members of the Japan Society of Gynecologic Oncology. The survey consisted of 25 questions in 4 categories: respondent demographics, HBOC management experience, insurance coverage of HBOC management, and educational opportunities related to HBOC.

Results

A total of 666 valid responses were received. Regarding the prevalence of HBOC practice, the majority of physicians responded in the negative and required human resources, information sharing and educational opportunities, and expanded insurance coverage to adopt and improve HBOC practice. Most physicians were not satisfied with the educational opportunities provided so far, and further expansion was desired. They remarked on the psychological burdens of many HBOC managements. Physicians reported these burdens could be alleviated by securing sufficient time to engage in HBOC management, creating easy-to-understand explanatory material for patients, collaboration with specialists in genetic medicine, and educational opportunities.

Conclusion

Gynecologic oncologists in Japan are struggling to deal with psychological burdens in HBOC practice. To promote the clinical practice of HBOC management, there is an urgent need to strengthen human resources and improve educational opportunities, and expand insurance coverage for HBOC management.

Japan Society of Gynecologic Oncology conducted a survey on the current status of hereditary breast and ovarian cancer (HBOC) practice. About half of the 666 respondents did not feel that HBOC practice had become common, and the majority answered HBOC practice in Japan was not widespread. There is a need to strengthen human resources and educational content, and to reexamine the items covered by insurance.

Functions of Breast Cancer Predisposition Genes: Implications for Clinical Management

Approximately 5–10% of all breast cancer (BC) cases are caused by germline pathogenic variants (GPVs) in various cancer predisposition genes (CPGs). The most common contributors to hereditary BC are BRCA1 and BRCA2, which are associated with hereditary breast and ovarian cancer (HBOC). ATM, BARD1, CHEK2, PALB2, RAD51C, and RAD51D have also been recognized as CPGs with a high to moderate risk of BC. Primary and secondary cancer prevention strategies have been established for HBOC patients; however, optimal preventive strategies for most hereditary BCs have not yet been established. Most BC-associated CPGs participate in DNA damage repair pathways and cell cycle checkpoint mechanisms, and function jointly in such cascades; therefore, a fundamental understanding of the disease drivers in such cascades can facilitate the accurate estimation of the genetic risk of developing BC and the selection of appropriate preventive and therapeutic strategies to manage hereditary BCs. Herein, we review the functions of key BC-associated CPGs and strategies for the clinical management in individuals harboring the GPVs of such genes.

Prevalence of Pathogenic Germline BRCA1/2 Variants and Their Association with Clinical Characteristics in Patients with Epithelial Ovarian Cancer in a Rural Area of Japan

The prevalence of germline BRCA1 or BRCA2 pathogenic variants (gBRCA1/2-PV) in patients with primary epithelial ovarian cancer (OC) in a rural area of Japan and their association with clinical characteristics, including treatment response and survival outcome, were investigated. A total of 123 unbiased patients with OC were tested for gBRCA1 and gBRCA2 using next-generation sequencing-based targeted amplicon sequencing. Clinical characteristics of OC patients with and without gBRCA1/2 status were compared. The overall prevalence of gBRCA1/2-PV was 15.4% (19 cases), with gBRCA2-PV (10.5%, 13 cases) being more common than gBRCA1-PV (4.9%, 6 cases). Among the observed gBRCA1/2-PV, several novel variants were included, suggesting that gBRCA1/2-PV unique to the local area exist. gBRCA1/2-PV was significantly more prevalent in OC patients at an older age, with high-grade serous carcinoma, with advanced-stage tumors, and with a family history of breast cancer or hereditary breast and ovarian cancer syndrome (HBOC)-associated cancers. Patients with advanced-stage OC with gBRCA1/2-PV showed a significantly lower recurrence rate and tended to have better progression-free and overall survival than those with wild-type gBRCA1/2. Genetic testing for gBRCA1/2 status in all OC patients is useful not only for diagnosing HBOC in patients and their relatives to assess the risk of HBOC-associated cancers, but also to estimate therapy response and outcomes in patients.

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.

Hereditary gynecologic tumors and precision cancer medicine

Gynecologic cancers are more often caused by genetic factors than other cancers. Genetic testing has become a promising avenue for the prevention, prognosis, and treatment of cancers. This review describes molecular features of gynecologic tumors linked to hereditary syndromes, gives an overview of the current state of clinical management, and clarifies the role of gynecology in the treatment of hereditary tumors. Typical hereditary gynecologic tumors include hereditary breast and ovarian cancer, Lynch syndrome, Peutz-Jeghers syndrome, and Cowden syndrome. Multigene panel testing, which analyzes a preselected subset of genes for genetic variants, has recently become the first-choice test because it can provide more accurate risk assessment than a single test. Furthermore, comprehensive genomic cancer profiling enables personalized cancer treatment and aids in germline findings.

Homologous Recombination Deficiencies and Hereditary Tumors

Homologous recombination (HR) is a vital process for repairing DNA double-strand breaks. Germline variants in the HR pathway, comprising at least 10 genes, such as BRCA1, BRCA2, ATM, BARD1, BRIP1, CHEK2, NBS1(NBN), PALB2, RAD51C, and RAD51D, lead to inherited susceptibility to specific types of cancers, including those of the breast, ovaries, prostate, and pancreas. The penetrance of germline pathogenic variants of each gene varies, whereas all their associated protein products are indispensable for maintaining a high-fidelity DNA repair system by HR. The present review summarizes the basic molecular mechanisms and components that collectively play a role in maintaining genomic integrity against DNA double-strand damage and their clinical implications on each type of hereditary tumor.

Retroperitoneal leiomyosarcoma in a female patient with a germline splicing variant RAD51D c.904-2A > T: a case report

Background

RAD51D (RAD51 paralog D) is an intermediate cancer susceptibility gene for primary ovarian cancer, including fallopian tube and peritoneal carcinomas and breast cancer. Although gynecological non-epithelial tumors such as uterine sarcomas are associated with genomic instability, including BRCA impairment, there is no clear evidence of the relationship between RAD51D variants and the risk of sarcoma development.

Case presentation

A Japanese woman in her 50s underwent multiple surgical resections and several regimens of chemotherapy for tumors that originated in the retroperitoneum and recurred in the peritoneum over a clinical course of approximately 4 years. The peritoneal tumor was histologically diagnosed as a leiomyosarcoma and was genetically identified to show a splice variant of RAD51D c.904-2A > T [NM_002878] through tumor profiling performed as a part of cancer precision medicine. The confirmatory genetic test performed after genetic counseling revealed that the RAD51D splicing variant detected in her tumor was of germline origin. In silico analyses supported the possible pathogenicity of the detected splice variant of RAD51D with a predicted attenuation in mRNA transcription and truncated protein production due to frameshifting, which was attributed to a single-nucleotide alteration in the splicing acceptor site at the 3′-end of intron 9 of RAD51D. Considering her unfavorable clinical outcome, which showed a highly aggressive phenotype of leiomyosarcoma with altered RAD51D, this case provided novel evidence for the relationship of a RAD51D splicing variant with malignant tumor development or progression. We report the findings of this rare case with possible involvement of the germline variant of RAD51D c.904-2A > T as a potential predisposing factor for malignant tumors, including leiomyosarcoma.

Conclusions

We present the findings of a case of leiomyosarcoma in the peritoneum of a female patient with a novel germline splicing variant of RAD51D as potential evidence for the pathogenicity of the variant and its involvement in the risk of sarcoma etiology and/or development. To the best of our knowledge, this is the first case report describing a leiomyosarcoma carrying a germline RAD51D splicing variant and elucidating its pathogenicity on the basis of computational prediction of the impairment of normal transcription and the presumed loss of functional protein production.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13053-021-00205-x.

Clinical and pathological analysis of companion diagnostic testing of microsatellite instability-high for pembrolizumab in gynaecologic malignancy

BACKGROUND

Microsatellite instability-high is a known biomarker for anti-PD-1/PD-L1 immune checkpoint therapy. It is also a known tumour feature of Lynch syndrome, detected most frequently in endometrial cancer. However, it remains unclear how microsatellite instability testing is carried out in the clinical field.

METHODS

Ninety-nine patients with gynaecological malignant tumours who underwent microsatellite instability testing as a companion diagnosis for pembrolizumab and 16 patients who previously underwent microsatellite instability testing as a screening for Lynch syndrome were recruited. Clinical information, microsatellite instability status, outcomes, genetic assessments and information about cancer tissue were retrospectively analysed.

RESULTS

Ninety-nine patients had 101 gynaecologic malignant tumours including 26 endometrial, 38 ovarian and 28 cervical cancers, 9 with other tumours including 2 synchronous endometrial and ovarian cancers. All tissue samples were successfully tested, even though some were ≥10-year-old samples. Three cases (3.0%, 3/99) showed microsatellite instability-high; all cases were endometrial cancers with one case of synchronous endometrial and ovarian cancer [11.5% (3/26) in endometrial cancer, 2.6% (1/38) in ovarian cancer], and there was no microsatellite instability-high in cervical and other cancers. One of the endometrial cancer patients received pembrolizumab treatment, but finally died of cancer. Two other cases underwent genetic testing; both were diagnosed as Lynch syndrome. Six cases (37.5%) showed microsatellite instability-high in screening for Lynch syndrome.

CONCLUSIONS

Microsatellite instability-high was less commonly detected as a companion diagnosis for pembrolizumab in unselected gynaecologic patients. Genetic counselling should be always provided along with treatment selection.

Probability of detecting germline BRCA1/2 pathogenic variants in histological subtypes of ovarian carcinoma. A meta-analysis

BACKGROUND

Histology restricted genetic predisposition testing of ovarian carcinoma patients is a topic of debate as the prevalence of BRCA1/2 pathogenic variants (PVs) in various histological subtypes is ambiguous. Our primary aim was to investigate the proportion of germline BRCA1/2 PVs per histological subtype. Additionally, we evaluated (i) proportion of somatic BRCA1/2 PVs and (ii) proportion of germline PVs in other ovarian carcinoma risk genes.

METHODS

PubMed, EMBASE and Web of Science were systematically searched and we included all studies reporting germline BRCA1/2 PVs per histological subtype. Pooled proportions were calculated using a random-effects meta-analysis model. Subsets of studies were used for secondary analyses.

RESULTS

Twenty-eight studies were identified. The overall estimated proportion of germline BRCA1/2 PVs was 16.8% (95% CI 14.6 to 19.2). Presence differed substantially among patients with varying histological subtypes of OC; proportions being highest in high-grade serous (22.2%, 95% CI 19.6 to 25.0) and lowest in clear cell (3.0%, 95% CI 1.6 to 5.6) and mucinous (2.5%, 95% CI 0.6 to 9.6) carcinomas. Somatic BRCA1/2 PVs were present with total estimated proportion of 6.0% (95% CI 5.0 to 7.3), based on a smaller subset of studies. Germline PVs in BRIP1, RAD51C, RAD51D, PALB2, and ATM were present in approximately 3%, based on a subset of nine studies.

CONCLUSION

Germline BRCA1/2 PVs are most frequently identified in high-grade serous ovarian carcinoma patients, but are also detected in patients having ovarian carcinomas of other histological subtypes. Limiting genetic predisposition testing to high-grade serous ovarian carcinoma patients will likely be insufficient to identify all patients with a germline PV.

BRCA Genetic Test and Risk-Reducing Salpingo-Oophorectomy for Hereditary Breast and Ovarian Cancer: State-of-the-Art

In the field of gynecology, the approval of the PARP inhibitors (PARPi) has been changing the treatment of ovarian cancer patients. The BRCA genetic test and the HRD test are being used as a companion diagnosis before starting PARPi treatment. BRACAnalysis CDx^® and Myriad myChoice^® HRD test are widely used as a BRCA genetic test and HRD test, respectively. In addition, FoundationOne^®CDx is sometimes used as a tumor BRCA test and HRD test. In clinical practice, gynecologists treating ovarian cancer are faced with making decisions such as whether to recommend the gBRCA test to all ovarian cancer patients, whether to perform the gBRCA test first or HRD test first, and so on. Regarding the judgment result of the HRD test, the cutoff value differs depending on the clinical trial, and the prevalence of gBRCA pathogenic variant rate is different in each histological type and country. A prospective cohort study showed that RRSO reduced all-cause mortality in both pre- and postmenopausal women; however, RRSO significantly reduced the risk of breast cancer for BRCA2 pathogenic variant carriers, but not for BRCA1 pathogenic variant carriers. Moreover, salpingectomy alone is said to not decrease the risk of developing ovarian or breast cancer, so further discussion is evidently required. We discuss the current situation and problems in doing BRCA genetic test and RRSO in this review article.

Germline and tumor BRCA1/2 mutations in Chinese high grade serous ovarian cancer patients

Background

Studies on the prevalence of BRCA1/2 mutations in ovarian cancer mainly focused on germline single-nucleotide variant (SNV)/insertion/deletion (indel). The status of large genomic rearrangement (LRG) and somatic mutation were poorly investigated.

Methods

Paired blood and tumor DNA from an unselected cohort of 115 Chinese high grade serous ovarian cancer (HGSOC) patients were collected and analyzed for BRCA1/2 SNV and indel by NGS. BRCA1/2 LRG was detected by MLPA. Clinicopathological characteristics including age at diagnosis, FIGO stage, family history and follow-up data were collected for further analysis.

Results

A total of 115 HGSOC patients were screened. Among them, 30 (26.1%) had germline BRCA1/2 mutations, including 19 (16.5%) SNV/indels, 5 (4.3%) LGRs in BRCA1, and 6 (5.2%) SNV/indels in BRCA2. Ten (8.7%) had somatic BRCA1/2 mutations, including 5 (4.3%) in BRCA1 and 5 (4.3%) in BRCA2. The entire tumor BRCA1/2 mutation frequency was 34.8%. No patients were found with two or more deleterious BRCA1/2 mutations. The proportion of germline (66.7%) and tumor (75%) mutation carriers was significantly increased for patients with family history when compared with those without (P<0.05). Patients with germline BRCA1/2 mutation appeared to be younger than non-carriers (mean age, 50.9 vs. 54.4 years, P=0.004) and somatic mutation carriers (mean age, 50.9 vs. 58.7 years, P=0.009). No significant association was found between BRCA1/2 status and clinicopathological characteristics including stage and family history of other cancer than breast and ovarian cancer. In univariate and Cox regression analysis, patients with tumor BRCA1/2 mutations had significant improvements than non-carriers in overall survival in the first two years after surgery (P<0.05). No significant impacts were found between various mutation status in PFS.

Conclusions

There is a high germline and tumor BRCA1/2 mutation incidences in Chinese HGSOC patients. Germline mutations were associated with family history and age at diagnosis, whereas somatic mutations were not. In our study, tumor BRCA1/2 mutations showed a time-depended improved survival outcome. A larger cohort should be examined to clarify the relation between BRCA1/2 mutation and survival outcomes.

The RAD51D c.82G>A (p.Val28Met) variant disrupts normal splicing and is associated with hereditary ovarian cancer

PURPOSE

Mutations in RAD51D are associated with a predisposition to primary ovarian, fallopian tube, and peritoneal carcinoma. Our study aims to characterize a RAD51D missense variant in a hereditary ovarian cancer family.

METHODS

The effects of the RAD51D c.82G>A (p.Val28Met) variant on mRNA splicing were evaluated and characterized using RT-PCR, cloning and DNA sequencing.

RESULTS

This variant completely disrupts normal splicing and results in the loss of 3'end of 5'UTR and the entire exon 1 (c.-86_c.82), which presumably leads to loss of the RAD51D protein. The RAD51D c.82G>A (p.Val28Met) variant is clinically significant and classified as likely pathogenic.

CONCLUSIONS

Our results indicate that the RAD51D c.82G>A (p.Val28Met) variant contributes to cancer predisposition through disruption of normal mRNA splicing. The identification of this variant in an individual affected with high-grade serous fallopian tube cancer suggests that the RAD51D variant may contribute to predisposition to the ovarian cancer in this family.

Risk factors for lymph node metastasis of ovarian, fallopian tube and primary peritoneal cancer in hereditary breast and ovarian cancer syndrome

BACKGROUND

To establish an individualized surgical strategy for lymphadenectomy in ovarian cancer patients with the germline BRCA1 and BRCA2 pathogenic variants (BRCA1+ and BRCA2+), we investigated the clinicopathological characteristics that are involved in the increased risk of lymph node metastasis.

METHODS

We retrospectively reviewed the data of Japanese women registered in the database of the Japanese Hereditary Breast and Ovarian Cancer Consortium, who underwent BRCA1 and BRCA2 genetic testing.

RESULTS

We evaluated the predictors of lymph node metastasis in all patients with the information of age at the diagnosis, disease site, histological subtype, 2014 FIGO stage, personal breast cancer history and family history; 233, 153 and 32 patients in the BRCA- (no pathogenic variant), BRCA1+ and BRCA2+ groups, respectively. The prevalence of lymph node metastasis was not markedly different between BRCA- (20.0%), BRCA1+ (18.4%) and BRCA2+ (26.2%). Multivariate analysis revealed an absence of a family history of ovarian cancer as an independent predictor for an increased risk of lymph node metastasis in BRCA1+, and the prevalence of lymph node metastasis was 11.7 and 42.0% in the groups with and without a family history of ovarian cancer, respectively. This subgroup without a family history of ovarian cancer did not show any correlation with a particular variant of BRCA1, including two common variants of c.188 T > A and c.2800C > T.

CONCLUSIONS

This study suggested that certain genetic factors related to the penetrance of hereditary breast and ovarian cancer syndrome altered the frequency of lymph node metastasis in BRCA1+ ovarian cancer, and family history may be useful to personalize the indication of lymphadenectomy.

Molecular Features and Clinical Management of Hereditary Gynecological Cancers

Hereditary gynecological cancers are caused by several inherited genes. Tumors that arise in the female reproductive system, such as ovaries and the uterus, overlap with hereditary cancers. Several hereditary cancer-related genes are important because they might lead to therapeutic targets. Treatment of hereditary cancers should be updated in line with the advent of various new methods of evaluation. Next-generation sequencing has led to rapid, economical genetic analyses that have prompted a concomitant and significant paradigm shift with respect to hereditary cancers. Molecular tumor profiling is an epochal method for determining therapeutic targets. Clinical treatment strategies are now being designed based on biomarkers based on tumor profiling. Furthermore, the National Comprehensive Cancer Network (NCCN) guidelines significantly changed the genetic testing process in 2020 to initially consider multi-gene panel (MGP) evaluation. Here, we reviewed the molecular features and clinical management of hereditary gynecological malignancies, such as hereditary breast and ovarian cancer (HBOC), and Lynch, Li–Fraumeni, Cowden, and Peutz–Jeghers syndromes. We also reviewed cancer-susceptible genes revealed by MGP tests.

Germline multigene panel testing revealed a BRCA2 pathogenic variant in a patient with suspected Lynch syndrome

There has been a rapid advance in germline multigene panel testing by next-generation sequencing, and it is being widely used in clinical settings. A 56-year-old woman suspected of having Lynch syndrome was identified as a BRCA2 pathogenic variant carrier by multigene panel testing. The patient was diagnosed with endometrial cancer at the age of 39 years, and total laparoscopic hysterectomy and bilateral salpingectomy were performed at the age of 49 years; however, bilateral oophorectomy was not performed at that time. As she had a family history of colorectal cancer and a history of endometrial cancer, Lynch syndrome was suspected. However, germline multigene panel testing revealed a pathogenic BRCA2 variant rather than pathogenic variants in mismatch repair genes. In this case, with conventional genetic risk assessment, we were unable to determine whether the patient had a high risk of hereditary breast and ovarian cancer; thus, germline multigene panel testing may provide valuable information to improve disease management strategies for patients in clinical settings. Particularly, germline multigene panel testing may be useful for detecting hereditary tumor syndromes if a patient does not present with a typical family history of cancer.

Clinical implications of next-generation sequencing-based panel tests for malignant ovarian tumors

Precision medicine based on cancer genomics is being applied in clinical practice. However, patients do not always derive benefits from genomic testing. Here, we performed targeted amplicon exome sequencing‐based panel tests, including 160 cancer‐related genes (PleSSision‐160), on 88 malignant ovarian tumors (high‐grade serous carcinoma, 27; endometrioid carcinoma, 15; clear cell carcinoma, 30; mucinous carcinoma, 6; undifferentiated carcinoma, 4; and others, 6 (immature teratoma, 1; carcinosarcoma, 3; squamous cell carcinoma, 1; and mixed, 1)), to assess treatment strategies and useful biomarkers for malignant ovarian tumors. Overall, actionable gene variants were found in 90.9%, and druggable gene variants were found in 40.9% of the cases. Actionable BRCA1 and BRCA2 variants were found in 4.5% of each of the cases. ERBB2 amplification was found in 33.3% of mucinous carcinoma cases. Druggable hypermutation/ultramutation (tumor mutation burden ≥ 10 SNVs/Mbp) was found in 7.4% of high‐grade serous carcinoma, 46.7% of endometrioid carcinoma, 10% of clear cell carcinoma, 0% of mucinous carcinoma, 25% of undifferentiated carcinoma, and 33.3% of the other cancer cases. Copy number alterations were significantly higher in high‐grade serous carcinoma (P < .005) than in other histologic subtypes; some clear cell carcinoma showed high copy number alterations that were correlated with advanced stage (P < .05) and worse survival (P < .01). A high count of copy number alteration was associated with worse survival in all malignant ovarian tumors (P < .05). Our study shows that targeted agents can be detected in approximately 40% of malignant ovarian tumors via multigene panel testing, and copy number alteration count can be a useful marker to help assess risks in malignant ovarian tumor patients.

Summary of BARD1 Mutations and Precise Estimation of Breast and Ovarian Cancer Risks Associated with the Mutations

Over the last two decades, numerous BARD1 mutations/pathogenic variants (PVs) have been found in patients with breast cancer (BC) and ovarian cancer (OC). However, their role in BC and OC susceptibility remains controversial, and strong evidence-based guidelines for carriers are not yet available. Herein, we present a comprehensive catalog of BARD1 PVs identified in large cumulative cohorts of ~48,700 BC and ~20,800 OC cases (retrieved from 123 studies examining the whole coding sequence of BARD1). Using these resources, we compared the frequency of BARD1 PVs in the cases and ~134,100 controls from the gnomAD database and estimated the effect of the BARD1 PVs on BC and OC risks. The analysis revealed that BARD1 is a BC moderate-risk gene (odds ratio (OR) = 2.90, 95% CIs:2.25–3.75, p < 0.0001) but not an OC risk gene (OR = 1.36, 95% CIs:0.87–2.11, p = 0.1733). In addition, the BARD1 mutational spectrum outlined in this study allowed us to determine recurrent PVs and evaluate the variant-specific risk for the most frequent PVs. In conclusion, these precise estimates improve the understanding of the role of BARD1 PVs in BC and OC predisposition and support the need for BARD1 diagnostic testing in BC patients.

BRIP1, RAD51C, and RAD51D mutations are associated with high susceptibility to ovarian cancer: mutation prevalence and precise risk estimates based on a pooled analysis of ~30,000 cases

Background

It is estimated that more than 20% of ovarian cancer cases are associated with a genetic predisposition that is only partially explained by germline mutations in the BRCA1 and BRCA2 genes. Recently, several pieces of evidence showed that mutations in three genes involved in the homologous recombination DNA repair pathway, i.e., BRIP1, RAD51C, and RAD51D, are associated with a high risk of ovarian cancer. To more precisely estimate the ovarian cancer risk attributed to BRIP1, RAD51C, and RAD51D mutations, we performed a meta-analysis based on a comparison of a total of ~ 29,400 ovarian cancer patients from 63 studies and a total of ~ 116,000 controls from the gnomAD database.

Results

The analysis allowed precise estimation of ovarian cancer risks attributed to mutations in BRIP1, RAD51C, and RAD51D, confirming that all three genes are ovarian cancer high-risk genes (odds ratio (OR) = 4.94, 95%CIs:4.07–6.00, p < 0.0001; OR = 5.59, 95%CIs:4.42–7.07, p < 0.0001; and OR = 6.94, 95%CIs:5.10–9.44, p < 0.0001, respectively). In the present report, we show, for the first time, a mutation-specific risk analysis associated with distinct, recurrent, mutations in the genes.

Conclusions

The meta-analysis provides evidence supporting the pathogenicity of BRIP1, RAD51C, and RAD51D mutations in relation to ovarian cancer. The level of ovarian cancer risk conferred by these mutations is relatively high, indicating that after BRCA1 and BRCA2, the BRIP1, RAD51C, and RAD51D genes are the most important ovarian cancer risk genes, cumulatively contributing to ~ 2% of ovarian cancer cases. The inclusion of the genes into routine diagnostic tests may influence both the prevention and the potential treatment of ovarian cancer.

Exome sequencing of familial high-grade serous ovarian carcinoma reveals heterogeneity for rare candidate susceptibility genes

High-grade serous ovarian carcinoma (HGSOC) has a significant hereditary component, approximately half of which cannot be explained by known genes. To discover genes, we analyse germline exome sequencing data from 516 BRCA1/2-negative women with HGSOC, focusing on genes enriched with rare, protein-coding loss-of-function (LoF) variants. Overall, there is a significant enrichment of rare protein-coding LoF variants in the cases (p < 0.0001, chi-squared test). Only thirty-four (6.6%) have a pathogenic variant in a known or proposed predisposition gene. Few genes have LoF mutations in more than four individuals and the majority are detected in one individual only. Forty-three highly-ranked genes are identified with three or more LoF variants that are enriched by three-fold or more compared to GnomAD. These genes represent diverse functional pathways with relatively few involved in DNA repair, suggesting that much of the remaining heritability is explained by previously under-explored genes and pathways.

Identification of novel mutations of ovarian cancer-related genes from RNA-sequencing data for Japanese epithelial ovarian cancer patients

Ovarian cancer has the highest mortality rate among gynecological cancers. Gene mutations are involved in the carcinogenesis, metastasis, and therapeutic response in ovarian cancer. However, the variety and proportion of gene mutation is not fully analyzed in Japanese ovarian cancer patients, especially, in those with recurrent tumors. In the present study, RNA-sequencing was performed for 32 clinical ovarian specimens obtained from 24 Japanese patients (24 primary cancer specimens and 8 recurrent specimens paired with corresponding primary cancer specimens). Mutations in 24 primary specimens were analyzed by comparing the sequence data mapped on RefSeq genes with those in the public online databases BRCA Exchange, COSMIC, ClinVar, and cBioportal. Mutations were observed in TP53 in 16 specimens (67%), BRCA1 in 9 (38%), BRCA2 in 13 (54%), ARID1A in 3 (13%), PIK3CA in 2 (8%), KRAS in 1 (4%), PTEN in 1 (4%), and CTNNB1 in 1 (4%), excluding synonymous mutations. Among those identified muations, 13 of 14 mutations in TP53, 10 of 11 mutations of BRCA1, 10 of 23 mutation positions of BRCA2, none of 7 mutations of ARID1A, 1 mutation of PIK3CA, and 1 mutation of CTNNB1 were consistent with those reported in the public online databases; however, the other mutations identified were novel. Comparison between matched-paired specimens of primary and recurrent tumors revealed the changes of mutational status in expressed RNAs. RNA-sequencing-based mutation analysis will be useful to reveal ethnic differences of gene mutations in ovarian cancer and to understand the contribution of gene mutations to recurrence.

The first Japanese nationwide multicenter study of BRCA mutation testing in ovarian cancer: CHARacterizing the cross-sectionaL approach to Ovarian cancer geneTic TEsting of BRCA (CHARLOTTE)

INTRODUCTION

BRCA gene mutations are associated with hereditary ovarian cancer. BRCA plays a key role in genome integrity, and mutations result in an increased risk for ovarian cancer. Although various guidelines recommend BRCA testing in patients with ovarian cancer, data on germline BRCA (gB RCA) mutation frequency in ovarian cancer in Japan are scarce.

OBJECTIVE

This study aimed to determine gBRCA1/2 mutations in Japanese patients with ovarian cancer, stratified by clinicopathological characteristics, and to assess patients' satisfaction with pre-test genetic counseling.

METHODS

The CHARLOTTE study (CHARacterizing the cross-sectionaL approach to Ovarian cancer: geneTic TEsting of BRCA; UMIN000025597) is the first large multicenter epidemiological survey of Japanese women, aged ≥20, with newly diagnosed ovarian cancer (epithelial, primary peritoneal, or fallopian tube cancer), with histologically confirmed specimens. Patients were enrolled sequentially and underwent pre-test genetic counseling for BRCA testing. Blood samples were centrally tested for the presence or absence of known gBRCA mutations. A questionnaire was used to assess patient satisfaction with pre-test genetic counseling.

RESULTS

A total of 634 patients with a mean age of 56.9 years were included. Most patients (84.2%) had epithelial ovarian cancer, and 51.1% had FIGO stage III-IV cancer. Nearly all patients (99.5%) received genetic counseling before the BRCA testing, either by an obstetrician-gynecologist (42.0%) or a clinical geneticist (42.0%). The overall prevalence of gBRCA1/2 mutations was 14.7% (93/634), with gBRCA1 mutations (9.9%) more common than gBRCA2 mutations (4.7%). High-grade serous carcinoma showed a prevalence of gBRCA mutations of 28.5%. Most patients were satisfied with pre-test counseling, irrespective of the service provider's professional position.

DISCUSSION

Patients with high-grade serous carcinoma and family history of ovarian cancer had a slightly higher prevalence of gBRCA mutations, but none of the subgroups had considerably high gBRCA mutation prevalence. These data suggest that gBRCA testing should be carried out in all patients with ovarian cancer.

Germline and somatic mutations of homologous recombination-associated genes in Japanese ovarian cancer patients

We explored the frequency of germline and somatic mutations in homologous recombination (HR)-associated genes in major histological types of ovarian cancer. We performed targeted sequencing to assess germline and somatic mutations of 16 HR-associated genes and 4 mismatch repair (MMR) genes among 207 ovarian cancer patients (50 high-grade serous carcinomas (HGSC), 99 clear cell carcinomas (CCC), 39 endometrioid carcinomas (EC), 13 mucinous carcinomas (MC), and 6 low-grade serous carcinomas (LGSC)). Germline or somatic mutations of HR-associated genes were detected in 44% of HGSC, 28% of CCC, 23% of EC, 16% of MC, and 17% of LGSC patients. The profile of HR-associated gene mutations was remarkably different among each histological type. Germline BRCA1/2 mutations were frequently detected in HGSC and were rarely observed in CCC, EC, and MC patients. ATM somatic mutation was more frequently detected in CCC (9%) and EC patients (18%) than in HGSC patients (4%). There was a positive correlation between MMR gene mutations and HR-associated gene mutations (p = 0.0072). Our findings might be useful in selection of ovarian cancer patients that should be treated with PARP inhibitors.

Establishment and characterization of a new malignant peritoneal mesothelioma cell line, KOG-1, from the ascitic fluid of a patient with pemetrexed chemotherapy resistance

Malignant peritoneal mesothelioma (MPeM) is a rare and aggressive form of malignant mesothelioma. Sufficient biological tools for studying the functional characteristics of this cancer have not been developed. Therefore, in this study, a novel human cancer cell line, KOG-1, was established from ascites fluids isolated from a 39-year-old Japanese woman with pemetrexed-resistant MPeM. Cells were dendritic or linear immediately after thawing, showed a jigsaw puzzle-like and spindle arrangement during growth, and formed monolayers without contact inhibition in two-dimensional (2D) culture. The population doubling time was 13.7 h. Karyotypic and molecular genetic analyses showed that chromosome numbers ranged from 62 to 142, with a peak of 73 with complicated copy number alterations. No germline BAP1 pathogenic variant was detected. Cells expressed various tumor markers of mesothelioma, such as calretinin, podoplanin, and Wilms tumor 1 (WT-1). Drug sensitivity and resistance testing with a set of 36 drugs using 2D and three-dimensional (3D) culture models demonstrated that KOG-1 cells showed high and low sensitivity to pemetrexed under 2D and 3D culture conditions, respectively, whereas control ovarian cancer cell lines showed low sensitivity to pemetrexed under both culture conditions. This newly established cell line will be a valuable biological resource to expand the feasibility of functional studies as well as drug testing for potential therapeutic purposes in MPeM.

Japan Society of Clinical Oncology provisional clinical opinion for the diagnosis and use of immunotherapy in patients with deficient DNA mismatch repair tumors, cooperated by Japanese Society of Medical Oncology, First Edition

Background

Novel therapeutic agents have improved survival outcomes in patients with advanced solid tumors. In parallel, the development of predictive biomarkers to identify patients who are likely to benefit from a certain treatment has also contributed to the improvement of survival. Recently, clinical trials have reported the efficacy of immune checkpoint inhibitors in the treatment of mismatch repair-deficient (dMMR) advanced solid tumors. In Japan, a PD-1 inhibitor for dMMR advanced solid tumors, regardless of the primary tumor site, has been approved. However, there are some issues related to administering immune checkpoint inhibitors in the clinical practice setting, making it necessary to develop the guidelines.

Methods

Clinical questions (CQs) regarding medical care were formulated for patients with dMMR advanced solid tumors, and evidence to the CQs was collected by manual search to prepare recommendations. Then, the committee members voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other factors.

Results

The current guideline, which we consider a provisional clinical opinion at this point, describes the 11 requirements to be considered in terms of patients for whom dMMR testing is recommended, the timing and methods of dMMR testing, and clinical care systems required to perform dMMR testing properly and to administer immune checkpoint inhibitors safely.

Conclusion

This provisional clinical opinion proposes the requirements for performing dMMR testing properly to select patients who are likely to benefit from immune checkpoint inhibitors and administering them safely.

Electronic supplementary material

The online version of this article (10.1007/s10147-019-01498-8) contains supplementary material, which is available to authorized users.

Challenges in Managing Patients with Hereditary Cancer at Gynecological Services

Aim

To reveal current problems and challenges faced by our gynecologic services department in managing patients with hereditary cancers.

Methods

We collected clinical data of patients with hereditary cancers, identified via genetic testing (or clinically diagnosed in cases of Cowden syndrome or Peutz–Jeghers syndrome), and treated in our gynecological department from 2012 to 2018.

Results

Fifteen patients had hereditary breast and ovarian cancer (HBOC), 6 had Lynch syndrome, 2 had Cowden syndrome, and 2 had Peutz–Jeghers syndrome. Five patients diagnosed with HBOC were younger than 40 years at diagnosis. Risk-reducing salpingo-oophorectomy (RRSO) was performed on 1 patient with a BRCA1 mutation at age 38 years. Seven patients overall underwent RRSO, and none had malignancies on pathological examinations. Peritoneal washing cytology (PWC) was suspicious for malignancy in one patient; however, subsequent PWC at 6 months after RRSO was negative. A patient with endometrial cancer and Lynch syndrome and a patient with atypical endometrial hyperplasia (AEH) and Cowden syndrome strongly desired fertility preservation. They achieved remission after medroxyprogesterone acetate treatment and multiple dilations and curettages, respectively. One patient with Lynch syndrome developed AEH after 11 years of surveillance. Laparotomy revealed adjacent low-grade and high-grade serous ovarian cancer with positive ascites cytology. She had no recurrence during 7-year follow-up after laparotomy.

Conclusion

Managing patients with hereditary cancer, positive or false-positive ascites cytology discovered during RRSO, and desired preservation of fertility is highly challenging.

Clinicopathologic features and BRCA mutations in primary fallopian tube cancer in Japanese women

Objective

The present study aimed to clarify the clinicopathological features, including the level of p53 protein expression and BRCA mutations, of primary fallopian tube cancer (PFTC) in Japanese women.

Methods

A multicenter clinical survey was conducted at three Japanese institutions. Clinical data in patients with PFTC between 1998 and 2016 were collected. Immunohistochemical staining of p53 and BRCA mutation analysis by exome sequence using paraffin-embedded surgical resected specimens were performed.

Results

A total of 40 patients with PFTC were enrolled in the study. The median age was 58 years (range: 38-78 years); 31 patients were menopausal. Thirty-four (85.0%) patients were diagnosed with serous adenocarcinoma (high grade, 33; low grade, 1). PFTC was classified into ampulla type, fimbriae type and undeterminable type by tumor-occupying lesion; ampulla type and fimbriae type occurred with the same frequency. Among 30 patients with high-grade serous adenocarcinoma, 6 patients showed germline mutations of BRCA1 (stop-gain 4 and frameshift deletion 2) and 2 patients showed germline mutation of BRCA2 (stop-gain 1 and frameshift deletion 1). However, only 1 patient had familial history of breast or ovarian cancer. Patients with BRCA mutations in the germline were frequently observed in ampulla type and FIGO stage I/II cancers, but no significant difference in the frequency of p53 overexpression and overall survival was observed.

Conclusions

Among Japanese patients with PFTC, 26.7% presented with BRCA mutations in the germline. Additionally, p53 was important for the carcinogenesis in fallopian tubes, independent of the specific BRCA mutation.

Prevalence and molecular characteristics of defective mismatch repair epithelial ovarian cancer in a Japanese hospital-based population

Background

The prevalence and molecular characteristics of defective mismatch repair epithelial ovarian cancers in the Japanese population have scarcely been investigated.

Methods

Immunohistochemistry for mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) was performed in formalin-fixed paraffin-embedded sections prepared from resected primary epithelial ovarian cancers in patients who underwent oophorectomy at our institution between April 2005 and September 2014. Genetic and/or epigenetic alterations of the mismatch repair genes were investigated in patients with loss of any mismatch repair proteins in the tumor.

Results

There were 305 patients with a median age of 54 years (range, 18-83 years). Loss of expression in the ovarian tumor of one or more mismatch repair proteins was observed in 3 of the 305 patients (0.98%): 2 patients MLH1/PMS2 loss and 1 patient showed MSH2/MSH6 loss. Genetic testing of these three patients failed to reveal any pathogenic germline mutations of MLH1 or MSH2. One patient with MLH1/PMS2 loss showed hypermethylation of the promoter region of MLH1. Somatic mutations were found in each of the alleles of MLH1 (c.545dupG and deletion of exons 2-19) in the other patient with MLH1/PMS2 loss. In the patient with MSH2/MSH6 loss, two somatic mutations were detected in MSH2 (c.229_230delAG and c.1861C>T), although we could not determine whether these mutations were biallelic or not.

Conclusions

The prevalence of defective mismatch repair epithelial ovarian cancer in the Japanese hospital-based population was extremely low. Molecular mechanism involved in such defective mismatch repair ovarian cancers seems to be epigenetic events through MLH1 promotor hypermethylation or somatically mutated mismatch repair genes without germline mismatch repair mutation.