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Numerous variants of unknown significance (VUSs) exist in hereditary breast and ovarian cancers. Although multiple methods have been developed to assess the significance of BRCA1/2 variants, functional discrepancies among these approaches remain. Therefore, a comprehensive functional evaluation system for these variants should be established. We performed conventional homologous recombination (HR) assays for 50 BRCA1 and 108 BRCA2 VUSs and complementarily predicted VUSs using a statistical logistic regression prediction model that integrated six in silico functional prediction tools. BRCA1/2 VUSs were classified according to the results of the integrative in vitro and in silico analyses. Using HR assays, we identified 10 BRCA1 and 4 BRCA2 VUSs as low-functional pathogenic variants. For in silico prediction, the statistical prediction model showed high accuracy for both BRCA1 and BRCA2 compared with each in silico prediction tool individually and predicted nine BRCA1 and seven BRCA2 variants to be pathogenic. Integrative functional evaluation in this study and the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines strongly suggested that seven BRCA1 variants (p.Glu272Gly, p.Lys1095Glu, p.Val1653Leu, p.Thr1681Pro, p.Phe1761Val, p.Thr1773Ile, and p.Gly1803Ser) and four BRCA2 variants (p.Trp31Gly, p.Ser2616Phe, p.Tyr2660Cys, and p.Leu2792Arg) were pathogenic. This study demonstrates that integrative evaluation using conventional HR assays and optimized in silico prediction comprehensively classified the significance of BRCA VUSs for future clinical applications., (© 2023. The Author(s), under exclusive licence to The Japan Society of Human Genetics.)

Substantial numbers of variants of unknown significance (VUSs) have been identified in BRCA1/2 through genetic testing, which poses a significant clinical challenge because the contribution of these VUSs to cancer predisposition has not yet been determined. Here, we report 10 Japanese patients from seven families with breast or ovarian cancer harboring the BRCA2 c.7847C>T (p.Ser2616Phe) variant that was interpreted as a VUS. This variant recurs only in families from Japan and has not been reported in the global general population databases. A Japanese patient with Fanconi anemia with compound heterozygous variants c.7847C>T (p.Ser2616Phe) and c.475+1G>A in BRCA2 was reported. In silico predictions and quantitative cosegregation analysis suggest a high probability of pathogenicity. The clinical features of the variant carriers were not specific to, but were consistent with, those of patients with hereditary breast and ovarian cancer. A validated functional assay, called the mixed-all-nominated-in-one-BRCA (MANO-B) method and the accurate BRCA companion diagnostic (ABCD) test, demonstrated the deleterious effects of the variant. Altogether, following the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines, this variant satisfied the "PS3," "PM2," "PM3," and "PP3" criteria. We thus conclude that the BRCA2 c.7847C>T (p.Ser2616Phe) variant is a "likely pathogenic" variant that is specifically observed in the Japanese population, leading to a breast and ovarian cancer predisposition., (© 2023 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Background: Risk-reducing mastectomy is one option for women with hereditary breast and ovarian cancer to reduce the risk of breast cancer., Patients and Methods: We analyzed data of the Japanese Organization of Hereditary Breast and Ovarian Cancer on women who were diagnosed as hereditary breast and ovarian cancer by BRCA germline genetic testing between 2010 and 2019 to reveal the rate and likelihood of risk-reducing mastectomy., Results: There were 412 women with BRCA1, 271 with BRCA2 and 4 with both female pathogenic variants. Ninety (13.1%) received risk-reducing mastectomy. The rates of risk-reducing mastectomy were statistically significantly higher in women with BRCA1 pathogenic variants than BRCA2, in women who had breast cancer than those who did not, in women with a breast cancer family history than in those without, in mothers than in those without children, in women who were receiving surveillance with MRI than those who were not and in women who received risk-reducing salpingo-oophorectomy than in those who did not on univariate analyses. The ages when they received the genetic testing were statistically significantly younger in the women receiving risk-reducing mastectomy than those who did not receive it. The women with BRCA1 pathogenic variants, personal history of breast cancer, mothers, those receiving MRI surveillance and younger women were independently significantly more likely to receive risk-reducing mastectomy based on multivariate analysis., Conclusions: The rate of risk-reducing mastectomy was not high in Japan; however, risk-reducing surgery was approved by the Japanese National Medical Insurance for hereditary breast and ovarian cancer patients with breast and/or ovarian cancer in 2020, so this rate will increase., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: BRCA1 and BRCA2 mutation carriers are recommended to undergo risk-reducing salpingo-oophorectomy (RRSO) by age 40 and 45, respectively. However, the carriers have a different way of thinking about their life plan. We aimed to investigate the distribution of age at diagnosis of ovarian cancer (OC) patients to examine the optimal timing of RRSO in the carriers., Methods: We examined a correlation between age at diagnosis of OC and common mutation types in 3,517 probands that received BRCA genetic testing. Among them, germline BRCA1 mutation (g BRCA1 m), germline BRCA2 mutation (g BRCA2 m) and germline BRCA wild-type (g BRCA wt) were found in 185, 42 and 241 OC patients, respectively., Results: The average age at diagnosis of OC in g BRCA1 m and g BRCA2 m was 51.3 and 58.3 years, respectively, and the difference from g BRCA wt (53.8 years) was significant. The g BRCA2 m carriers did not develop OC under the age of 40. The average age was 50.1 years for L63X and 52.8 years for Q934X in BRCA1 , and 55.1 years for R2318X and 61.1 years for STOP1861 in BRCA2 . The age at diagnosis in L63X or R2318X carriers was relatively younger than other BRCA1 or BRCA2 carriers, however their differences were not significant. With L63X and R2318X carriers, 89.4% (42/47) and 100% (7/7) of women were able to prevent the development of OC, respectively, when RRSO was performed at age 40., Conclusion: There appears to be no difference in the age at diagnosis of OC depending on the type of BRCA common mutation. Further analysis would be needed., Competing Interests: Masayuki Sekine received lecture fees from AstraZeneca. Takayuki Enomoto received lecture fees from AstraZeneca and Chugai Pharmaceutical. Seigo Nakamura received an honoraria for a seminar presentation from AstraZeneca and KONICA MINOLTA. The other authors declare no conflicts of interest., (Copyright © 2022. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology, and Japan Society of Gynecologic Oncology.)

We previously reported that L63X and Q934X are BRCA1 common founder variants in Japan. So far, there have been no reports of a correlation between such BRCA common variants and the risk of BRCA-related cancers. In this analysis, we investigated the correlation between the risk of ovarian cancer (OC) and BRCA recurrent pathogenic variants. We examined the database of the Japanese organization of hereditary breast and ovarian cancer. The database contained 3517 probands who underwent BRCA genetic testing. Among them, 11.1% (392/3517) had germline BRCA1 pathogenic variant, and 8.3% (293/3517) had BRCA2 pathogenic variant. We calculated the OC prevalence, breast cancer (BC) prevalence, and the ratio of OC to BC within second-degree relatives. The ratio of OC to BC in Q934X family members was significantly higher than that in the overall BRCA1 family members (0.80 vs.0.52: p = 0.038), and the ratio in STOP799 was 0.42, which was relatively lower than the overall BRCA1 value. Both Q934X and STOP799 are located in the ovarian cancer cluster region (OCCR), however there seems to be a difference in the risk of OC. R2318X family members had a significant higher ratio of OC to BC at 0.32 than the overall BRCA2 value of 0.13 (p = 0.012). R2318X is known to be located in the OCCR. This is the first report to investigate the correlation between BRCA recurrent variants and the risk of OC in Japan. The family members of probands with Q934X or R2318X have a higher risk of OC than that with other BRCA variants., (© 2021. The Author(s), under exclusive licence to The Japan Society of Human Genetics.)

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., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Background: This study aimed to identify the clinical background and treatment outcomes of risk-reducing salpingo-oophorectomy (RRSO) in Japan for women with hereditary breast and ovarian cancer (HBOC)., Methods: In the present retrospective observational study, we examined the Japanese HBOC Consortium's (JHC) database. This database contains 11,711 probands who received BRCA genetic testing, or their relatives, with any cancer in 2433 pedigrees. This study was supported by the registration committee of the JHC., Results: We analyzed 488 individuals diagnosed with HBOC, of which 153 (31.4%) underwent RRSO. Of the latter patients, 88 carried BRCA1 mutation (B1); 62 carried BRCA2 mutation (B2); and 3 carried both mutations. During a mean follow-up period of 2.6 years (range 0-12.6), one patient developed a primary peritoneal cancer (PPC). Clinical background comparison for individuals who underwent RRSO vs. those > 45 years of age who did not undergo RRSO revealed that significant factors were represented by B1 (p < 0.0001); child bearing (p < 0.00001); and breast cancer history (p < 0.01). However, family history of ovarian cancer and menopause status were not significantly different., Conclusion: Over 30% HBOC's in Japan underwent RRSO. In Japan, individuals with breast cancer history and B1 generally underwent RRSO, whereas those who did not bear a child mostly avoided RRSO.

Purpose: Prophylactic surgery is a preemptive strategy for hereditary breast and ovarian cancer (HBOC). Prophylactic mastectomy (PM) reduces breast cancer risk by > 90%. The aim of our study is to analyze the information of the Japanese pedigrees and to utilize the results for clinical practice., Methods: We statistically analyzed records of HBOC registrees who had undergone BRCA1/2 genetic testing at seven medical institutions up until 2016. In the cases of PM, we examined breasts with the use of mammography (MMG), ultrasound (US), and magnetic resonance imaging (MRI) before surgery. After PM, the specimens were divided about 1 cm serially and examined in their entirety., Results: Of 1527 registrees who underwent BRCA testing, 1125 (73.7%) were negative for BRCA1/2 mutation, 297 (19.5%) were positive for BRCA1/2 mutation (BRCA1/2 MUT+ ), and 105 (6.9%) had uncertain results. To decide whether to undergo total mastectomy vs. breast-conserving surgery (BCS), 370 registrees underwent presurgical genetic testing. During the follow-up period, four new-onset breast cancers were found among the 55 non-affected BRCA carriers. Among the 73 BRCA1/2 MUT+ carriers who underwent BCS, 3 were found to have ipsilateral breast cancer. Of 189 BRCA1/2 MUT+ carriers with unilateral breast cancer, 8 were found to have contralateral breast cancer. Of 53 PM specimens, 6 (11.3%) were found to have occult breast cancer despite using MMG, US, and MRI., Conclusions: Our report showed a relatively higher incidence rate of occult cancer at 11.3% in PM specimens despite thorough pre-operative radiological evaluations, which included a breast MRI. Considering the occult cancer rates and the various pathological methods of our study and published studies, we propose the necessity of a histopathological protocol.

Background: Cost-effectiveness analysis is an important aspect of healthcare, including in Japan, where preventive measures for BRCA1/2 mutation carriers are not covered by health insurance., Methods: We developed Markov models in a simulated cohort of women aged 35-70 years, and compared outcomes of surveillance with risk-reducing mastectomy (RRM) at age 35, risk-reducing salpingo-oophorectomy (RRSO) at age 45, and both (RRM&RRSO). We used breast and ovarian cancer incidences and adverse event rates from the previous studies, adjuvant chemotherapy, and hormonal therapy rates from the Hereditary Breast and Ovarian Cancer Registration 2015 in Japan, mortality rates from the National Cancer Center Hospital, Japan Society of Clinical Oncology, and Ministry of Health, Labour and Welfare, and direct costs from St. Luke's International Hospital and Keio University Hospital. We used previously published preference ratings of women without known high risk to adjust survival for quality of life. The discount rate was 2%., Results: Compared with surveillance, RRSO and RRM&RRSO were dominant (both cost-saving and more effective), and RRM was cost-effective in BRCA1 mutation carriers, while RRM and RRM&RRSO were dominant and RRSO was cost-effective in BRCA2. Among the four strategies including surveillance, RRM&RRSO and RRM were the most cost-effective in BRCA1 and BRCA2 mutation carriers, respectively., Conclusions: With quality adjustment, RRM, RRSO, and RRM&RRSO were all cost-effective preventive strategies in BRCA1/2 mutation carriers, with RRM&RRSO being the most cost-effective in BRCA1 and RRM in BRCA2. This result supports the inclusion of insurance coverage for BRCA mutation carriers in Japan.

Objective: This study investigated the psychosocial aspects of risk-reducing salpingo-oophorectomy in Japan., Methods: The subjects were 16 patients who underwent risk-reducing salpingo-oophorectomy at the Cancer Institute Hospital. Worry about cancer, emotional state and cancer-specific distress level were evaluated using a four-point Likert scale, the Profile of Mood States-Short Form and the Impact of Event Scale-Revised, respectively, before and 1 year after the surgery. In addition, the subjects were interviewed regarding their expectation for the risk-reducing surgery, the effects of the surgery, and the recovery from surgery, before the surgery and at 1, 6 and 12 months after the surgery. A t-test or Wilcoxon rank-sum test was used for the analysis, and literal analects were prepared for the interview and the answers were organized per question item using NVIVO10., Results: The results revealed that the total score for worry about breast cancer and ovarian cancer (P = 0.021) as well as the Impact of Event Scale-Revised (P = 0.021) were significantly lower 1 year after surgery, compared with the values before the surgery. Regarding the preoperative expectations for the surgery, the expectation for reducing the cancer risk was the highest. The reported effects of risk-reducing salpingo-oophorectomy on life included the appearance of menopausal symptoms, a loss of motivation and poor concentration; more effects were reported at 1 year after surgery than at 6 months after surgery., Conclusions: These results suggest that risk-reducing salpingo-oophorectomy can be effective for reducing worry about breast cancer and ovarian cancer and cancer-specific distress as well as contributing to a reduction in mortality from fallopian tube and ovarian related cancer., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The recognition of hereditary breast and ovarian cancer (HBOC) is gradually spreading in Japan after a famous American actress made it public that she underwent risk-reducing mastectomy (RRM) based on mutation of BRCA1. HBOC is a cancer susceptibility syndrome involving breast, ovarian, or prostate cancers due to germline mutation of BRCA1 or BRCA2. Although the frequency is low, genomic rearrangement is also found in Japan; therefore, in addition to PCR-direct sequencing, multiplex ligation-dependent probe amplification (MLPA) should be performed in genetic testing for HBOC. Recently, candidate genes other than BRCA1/2, such as RAD51C, PALB2, and BRIP1, have been identified for hereditary breast cancers. Variants of uncertain significance are seen in approximately 4-6% of all genetic testing reports for BRCA1/2. ACMG recommends the use of the term"variant"in addition to a modifier such as pathogenic, benign, and so on, instead of terms such as mutation or polymorphism. The incidence of ovarian cancer is not increased in women from breast cancer-only families that test negative for BRCA1/2 mutations. Therefore, intensive gynecological surveillance may not be needed for these clients. Basic data such as penetrance and cumulative risks of HBOC in Japanese populations are insufficient for risk assessment in genetic counseling. The Japanese HBOC consortium was established, and as one of the activities of the consortium, the registration project will start to provide essential genetic information in clinical practice. In Japan risk-reducing surgeries are, albeit gradually, increasingly being performed to potentially protect mutation carriers against HBOC. Risk-reducing salpingo-oophorectomy (RRSO) is effective in the reduction of the incidence of breast cancer, as well as of ovarian cancer. Furthermore, RRSO is associated with improved overall survival in BRCA1/2 mutation carriers. RRM also reduces the risk of breast cancer by more than 90%, but the survival benefit remains unknown. Recently, contralateral RRM has shown improved overall survival in a prospective analysis. Pathological examination of resected surgical specimens from RRSO revealed that some serous ovarian carcinomas originated from fimbriae of the uterine tube, showing focal p53 overexpression (p53 signature) in the tubal epithelium. Therefore, initial bilateral salpingectomy followed by a delayed oophorectomy may be a proposed alternative to RRSO, but there is no prospective evidence on the efficacy of bilateral salpingectomy.

In Japan, awareness of hereditary breast and ovarian cancer (HBOC) has gradually increased among health care workers and the general population. We focus on two current topics: genetic testing and risk-reducing surgery for HBOC. Genetic testing for BRCA1 and BRCA2, the genes responsible for HBOC, is performed to diagnose HBOC. PCR-direct sequencing is a standard method used for BRCA1/2 mutation analysis. Recently, genetic rearrangement of BRCA1 was reported in a Japanese patient with HBOC. Therefore, MLPA tests are also being included in routine genetic testing for the disease. The result of "uncertain significance, " which indicates unclear pathogenic significance, is obtained in about 3% of all patients who undergo BRCA1/2 genetic tests. Furthermore, novel candidate genes for HBOC, such as RAD51C, PALB2, and BRIP1, were recently identified. Prophylactic surgical intervention for HBOC includes procedures such as risk-reducing bilateral salpingo-oophorectomy (RRSO) and risk-reducing mastectomy(RRM). In Japan, RRSO is performed in very few patients at present. Increasing evidence from overseas indicates that RRSO contributes to a decreased incidence of ovarian/breast cancers and lowers overall mortality. Therefore, a system for performing RRSO was established in our institute. RRSO was approved to be performed as a clinical examination by our Institutional Review Board. The clinical significance of ipsilateral complete mastectomy and RRM remains unclear. Based on the NCCN guidelines, conservative mastectomy with radiation therapy is relatively contraindicated in patients with HBOC. However, several studies have reported that conservative mastectomy with radiation the rapydoes not increase the incidence of recurrent or metachronous breast cancers in the ipsilateral breast of mutation-positive patients when compared to mutation-negative or control patients. However, more aggressive malignancies seem to be included in the mutation-positive group(especially BRCA1 -mutation-positive cases). RRM clearly reduced the incidence of breast cancers. RRM may also be allowed as a treatment option for HBOC in Japan.

The prevalence of BRCA1/2 germline mutations in Japanese patients suspected to have hereditary breast/ovarian cancer was examined by a multi-institutional study, aiming at the clinical application of total sequencing analysis and validation of assay sensitivity in Japanese people using a cross-sectional approach based on genetic factors estimated from personal and family histories. One hundred and thirty-five subjects were referred to the genetic counseling clinics and enrolled in the study. Full sequencing analysis of the BRCA1/2 gene showed 28 types of deleterious mutations in 36 subjects (26.7%), including 13 types of BRCA1 mutations in 17 subjects (12.6%) and 15 types of BRCA2 mutations in 19 subjects (14.1%). Subjects were classified into five groups and 22 subgroups according to their personal and family history of breast and/or ovarian cancer, and the prevalence of deleterious mutations was compared with previously reported data in non-Ashkenazi individuals. Statistical analysis using the Mantel-Haenszel test for groups I through IV revealed that the prevalence of Japanese subjects was significantly higher than that of non-Ashkenazi individuals (P = 0.005, odds ratio 1.87, 95% confidence interval 1.22-2.88). Family history of the probands suffering from breast cancer indicated risk factors for the presence of deleterious mutations of BRCA1/2 as follows: (1) families with breast cancer before age 40 within second degree relatives (P = 0.0265, odds ratio 2.833, 95% confidence interval 1.165-7.136) and (2) families with bilateral breast cancer and/or ovarian cancer within second degree relatives (P = 0.0151, odds ratio 2.88, 95% confidence interval 1.25-6.64).

About 60% of familial breast and ovarian cancers in Japan involve germline mutations of the BRCA1 or BRCA2 ( BRCA1/2) genes. These genes contribute to genetic stability and DNA repair and act as tumor suppressor genes. Mutation analysis of the BRCA1/2 genes has improved our understanding of both common mutation patterns in Japanese patients and the clinicopathological features of BRCA1/2-related cancers. BRCA1-related breast cancers are characterized by poor prognosis, a low rate of estrogen receptor positivity, and histological predominance of solid-tubular carcinoma. BRCA1-related ovarian cancers are associated with a high frequency of serous adenocarcinoma and a good outcome. Further large-scale studies are needed to delineate genotype-phenotype relations and penetrance in BRCA1/2-related breast and ovarian cancers in Japan. The development of systems for clinical genetics in Japan, including genetic counseling, has led to the increased use of genetic testing for the clinical management of BRCA1/2-related cancers. Three options are available for carriers of BRCA1/2 mutations: intensive surveillance, chemoprevention, and prophylactic surgery. Studies done in other countries indicate that prophylactic surgery effectively prevents the development of breast and ovarian cancers in carriers of BRCA1/2 mutations. However, prophylactic mastectomy remains controversial in Japan, and now systematic intensive surveillance is generally performed for the prevention of breast cancer in women at high risk. Early detection of ovarian cancer remains challenging, resulting in increased acceptance of the need for prophylactic oophorectomy in women at risk. This review summarizes experimental and clinical findings about familial breast and ovarian cancers, including data on Japanese patients.