Prevalence and clinical characterization of BRCA1 and BRCA2 mutations in Korean patients with epithelial ovarian cancer

This study was performed to investigate the prevalence, clinical characteristics, and treatment response according to BRCA1 and BRCA2 (BRCA) mutations in Korean patients with epithelial ovarian cancer (EOC). Two‐hundred and ninety‐eight Korean women diagnosed with high‐grade serous and/or endometrioid EOC from 2010 to 2015 were tested for germline and 86 specimens for somatic BRCA mutations, regardless of the family history. Clinical characteristics including survival outcomes were compared in patients with and without BRCA mutations (NCT02963688). A total of 43 different germline BRCA mutations were identified in 78 patients among 298 patients (26.2%). Somatic BRCA mutations were identified in 11 (12.8%) patients among patients without germline BRCA mutations. Haplotype analysis demonstrated no founder mutations in our Korean patient cohort. Insignificant differences in age at diagnosis, primary site, and residual disease after surgery were observed between patients with and without BRCA mutations. In multivariate analysis for overall survival (OS), the presence of BRCA mutation was significantly associated with OS (P = .049) in addition to platinum sensitivity (P < .001), indicating it is an independent prognostic factor for survival regardless of platinum sensitivity to first‐line chemotherapy. In addition, a higher response rate to subsequent chemotherapy after recurrence was observed in EOC patients with BRCA mutations resulting in better OS. In the current study, the prevalence of BRCA mutations in Korean patients with EOC was higher than previously reported in other ethnic groups. We demonstrated characteristics and treatment response in Korean EOC patients with BRCA mutations. These findings may provide valuable information to be considered in future clinical trials including Asian patients.

Clinical and Genetic Characteristics of BRCA1/2 Mutation in Korean Ovarian Cancer Patients: A Multicenter Study and Literature Review

Purpose

We investigated the clinical relevance and spectrum of BRCA1/2 mutations in Korean ovarian cancer (KoOC) patients.

Materials and Methods

Two hundred seventy-nine KoOC patients were enrolled from three university hospitals between 2012 and 2017. Their peripheral blood samples were obtained for BRCA1/2 mutation analysis by direct sequencing. Clinicopathological characteristics were retrospectively reviewed, and spectrum analyses of BRCA1/2 mutation were assessed by systematic literature review.

Results

Frequency of BRCA1/2 mutations was 16.5% in KoOC patients. BRCA1/2 mutations were significantly associated with family history of breast/ovarian cancer (p<0.001), serous histology (p=0.044), and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (III/IV, p=0.018) but not with early age-of-onset (age < 50, p=0.729). Literature review of BRCA1/2 mutations in KoOC patients found 111 (55 distinct) mutations with high proportion of Korean-specific mutations (24/55, 43.6%). Comparing the spectrum of BRCA1/2 mutation between KoOC and Korean breast cancer (KoBC) patients, the ratio of BRCA1-to-BRCA2 mutations was different, with BRCA1 (78.4%) being predominant in KoOC and BRCA2 in KoBC (59.2%). The most common mutation also differed between the two (c.3627insA of BRCA1 in KoOC and c.7480C>T of BRCA2 in KoBC).

Conclusion

The clinical relevance of BRCA1/2 mutations in KoOC patients was confirmed but that of early age-of-onset was not. Possible inconsistency in the ratio of BRCA1-to-BRCA2 mutations and the most common mutation between KoOC and KoBC may probably suggest presence of mutation sequence-associated penetrance tendency in hereditary Korean breast and ovarian cancer. These data may provide insights for optimal genetic counseling and prophylactic treatment for at-risk relatives of KoOC patients.

The Novel Pathogenic Mutation c.849dupT in BRCA2 Contributes to the Nonsense-Mediated mRNA Decay of BRCA2 in Familial Breast Cancer

In this study, we used next-generation sequencing methods to screen 300 individuals for BRCA1 and BRCA2. A novel mutation (c.849dupT) in BRCA2 was identified in a female patient and her unaffected brothers. This mutation leads to the truncation of BRCA2 functional domains. Moreover, BRCA2 mRNA expression levels in mutation carriers are significantly reduced compared to noncarriers. Immunofluorescence and western blot assays showed that this mutation resulted in reduced BRCA2 protein expression. Thus, we identified a novel mutation that damaged the function and expression of BRCA2 in a family with breast cancer history. The pedigree analysis suggested that this mutation is strongly associated with familial breast cancer. Genetic counsellors suggest that mutation carriers in this family undergo routine screening for breast cancer, as well as other malignancies, such as prostate and ovarian cancer. The effects of this BRCA2 mutation on drug resistance should be taken into consideration during treatment.

Expression of DNA Damage Response Proteins and Associations with Clinicopathologic Characteristics in Chinese Familial Breast Cancer Patients with BRCA1/2 Mutations

Purpose

The characteristic expression of DNA damage response proteins in familial breast cancers with BRCA1, BRCA2, or non-BRCA1/2 mutations has not been analyzed in Chinese patients. Our study aimed to assess the differential expression of microcephalin 1 (BRIT1), ATM serine/threonine kinase (ATM), checkpoint kinase 2 (CHEK2), BRCA1, RAD51 recombinase (RAD51), and poly (ADP-ribose) polymerase 1 (PARP-1) and establish the profile of Chinese familial breast cancers with different mutation status.

Methods

We constructed five tissue microarrays from 183 familial breast cancer patients (31 with BRCA1 mutations; 14 with BRCA2 mutations, and 138 with non-BRCA1/2 mutations). The DNA response and repair markers used for immunohistochemistry analysis included BRIT1, ATM, CHEK2, BRCA1, RAD51, and PARP-1. The expressions of these proteins were analyzed in BRCA1/2 mutated tumors. The association between pathologic characteristics with BRCA1/2 mutation status was also analyzed.

Results

In familial breast cancer patients, BRCA1 mutated tumors were more frequent with high nuclear grade, estrogen receptor/progesterone receptor/human epidermal growth factor receptor 2 negative, low Ki-67, and positive CK5/6. BRCA1 mutated tumors had lower CHEK2 and higher cytoplasmic BRIT1 expression than BRCA2 and non-BRCA1/2 mutation tumors. BRCA2-associated tumors showed higher CHEK2 and cytoplasmic RAD51 expression than those in other groups. Nuclear PARP-1 expression in BRCA1/2-associated tumors was significantly higher than in non-BRCA1/2 mutation tumors. Moreover, we found quite a few of negative PARP-1 expression cases in BRCA1/2 mutated groups.

Conclusion

The clinicopathologic findings of BRCA1-associated Chinese familial breast cancers were similar to the results of other studies. Chinese familial breast cancer patients with BRCA1/2 mutations might have distinctive expression of different DNA damage response proteins. The reduced expression of PARP-1 in Chinese BRCA1/2 mutated breast cancer patients could influence the therapeutic outcome of PARP-1 inhibitors.

Peritoneal carcinomatosis after risk-reducing surgery in BRCA1/2 mutation carriers

BACKGROUND

Risk-reducing salpingo-oophorectomy (RRSO) is recommended for BRCA1/2 mutation carriers because of their increased risk of ovarian carcinoma. Despite RRSO, metachronous peritoneal carcinomatosis occasionally is diagnosed.

METHODS

The literature was searched for BRCA1/2 mutation carriers with peritoneal carcinomatosis after risk-reducing surgery. The authors were asked for additional data. Clinical and histopathological data were descriptively analyzed. Cases were compared with a single-institution control cohort.

RESULTS

Of 36 cases, 86.1% concerned BRCA1 mutation carriers. The median age of the patients was 52 years (range, 30-71 years) at the time of risk-reducing surgery and 60 years (range, 37-75 years) at the time of diagnosis of peritoneal carcinomatosis. The median interval between the 2 events was 54.5 months (range, 11-292 months). Peritoneal carcinomatosis was mostly high-grade serous carcinoma. Histopathological details of the RRSO specimens were retrieved in 8 cases; 5 (62.5%) were found to have serous tubal intraepithelial carcinoma and 1 had epithelial atypia. Cases were older (P = .025) at the time of risk-reducing surgery and harbored more serous tubal intraepithelial carcinomas (P<.001) compared with women from the control cohort.

CONCLUSIONS

Metachronous peritoneal carcinomatosis after risk-reducing surgery occurs predominantly in BRCA1 mutation carriers, usually within 5 years. Data have suggested that surgery at a younger age lowers the rates of peritoneal carcinomatosis. These data can be used in the gynecologic counseling of BRCA1/2 mutation carriers. RRSO should include complete salpingectomy. Detailed histopathological examination of specimens removed during RRSO is essential. Cancer 2018;124:952-9. © 2018 American Cancer Society.

The Effect of Reproductive Factors on Breast Cancer Presentation in Women Who Are BRCA Mutation Carrier

PURPOSE

Germline mutations in the BRCA1 and BRCA2 genes confer increased risks for breast cancers. However, the clinical presentation of breast cancer among women who are carriers of the BRCA1 or BRCA2 (BRCA1/2 carriers) mutations is heterogenous. We aimed to identify the effects of the reproductive histories of women with the BRCA1/2 mutations on the clinical presentation of breast cancer.

METHODS

We retrospectively analyzed clinical data on women with proven BRCA1 and BRCA2 mutations who were recruited to the Korean Hereditary Breast Cancer study, from 2007 to 2014.

RESULTS

Among the 736 women who were BRCA1/2 mutation carriers, a total of 483 women had breast cancers. Breast cancer diagnosis occurred at significantly younger ages in women who experienced menarche at ≤14 years of age, compared to those who experienced menarche at >14 years of age (37.38±7.60 and 43.30±10.11, respectively, p<0.001). Additionally, the number of full-term pregnancies was significantly associated with the age of diagnosis, especially in women with the BRCA2 mutation. The prevalence of advanced stages (stage II or III vs. stage I) of disease in parous women was higher than in nulliparous women (68.5% vs. 55.2%, p=0.043). This association was more pronounced in women with the BRCA2 mutation (hazard ratio, 2.67; p=0.014).

CONCLUSION

Our results suggest that reproductive factors, such as the age of onset of menarche and the presence of parity, are associated with the clinical presentation patterns of breast cancer in BRCA1/2 mutation carriers.

Bilateral Triple-Negative Invasive Breast Cancer with a BRCA2 Mutation, and Glioblastoma: A Case Report and Literature Review

Breast cancer is the second leading cause of death among women in North America. Glioblastoma is the most common primary malignant central nervous system tumor in adults. The majority of hereditary breast cancers are associated with deleterious mutations in the BRCA1 and BRCA2 genes. Although few case reports have described the incidence of glioblastoma in patients previously diagnosed with breast cancer, any association between BRCA2 mutations and glioblastoma has not been demonstrated to date. Herein, we report a woman who is a carrier of a familial BRCA2 mutation, and was previously diagnosed with triple-negative breast cancer (TNBC) and subsequently with a second primary TNBC and glioblastoma. Further investigation is required to define the possible relationship between these two aggressive malignances and the BRCA2 mutation, which might be critical for the proper management and treatment of this disease.

Participation of Korean families at high risk for hereditary breast and ovarian cancer in BRCA1/2 genetic testing

OBJECTIVE

The aim of our study was to determine the rate of participation in genetic testing, to determine the reasons for non-participation and to identify the factors affecting participation in BRCA genetic testing for high-risk patients.

METHODS

This study was performed through a retrospective review of 804 individuals who underwent genetic counseling for BRCA1/2 gene mutations at Seoul National University Bundang Hospital between July 2003 and September 2012.

RESULTS

In total, 728 (90.5%) individuals underwent BRCA1/2 mutation screening after the initial genetic counseling; 88.2% of 647 probands and 100% of 157 family members were screened. In multivariate analysis, family history of breast cancer and younger age were independent variables affecting participation in genetic testing. Of the 132 people who initially declined genetic testing, 58 (43.9%) postponed the decision, 30 (22.7%) needed time to discuss the issue with family members, 22 (16.7%) did not want to know if they had a BRCA1/2 mutation, and 22 (16.7%) declined the test because of financial problems. When analyzing refusal of testing according to the time period before and after the implementation of national health insurance coverage for BRCA1/2 genetic testing, the critical reason given for refusal was different. After insurance coverage, refusal for financial reason was decreased from 61.1 to 9.6%.

CONCLUSIONS

A family history of breast cancer and a younger age were important factors associated with participation in genetic testing. National health insurance decreased the proportion of individuals who did not participate in testing owing to a financial reason. In genetic counseling, we have to understand these issues and consider several factors that may influence an individual's decision to be tested.

Characteristics of BRCA1/2 Mutation-Positive Breast Cancers in Korea: A Comparison Study Based on Multicenter Data and the Korean Breast Cancer Registry

Purpose

Mutations in BRCA genes are the main cause of hereditary breast cancer in Korea. The aim of this study was to investigate the characteristics of breast cancers involving BRCA1 (BRCA1 group) and BRCA2 (BRCA2 group) mutations.

Methods

We retrospectively reviewed the medical records of patients with BRCA1 (BRCA1 group) or BRCA2 (BRCA2 group) mutation positive breast cancer from multiple centers and compared the data to that of the Korean Breast Cancer Society registry (registry group).

Results

The patients of the BRCA1 group were diagnosed at a younger age (median age, 37 years) and had tumors of higher histological (61.3% with histological grade 3) and nuclear (37.5% with nuclear grade 3) grade than those of the registry group. In addition, the frequency of ductal carcinoma in situ in the BRCA1 group was lower (3.7%) than in the registry group, and the BRCA1 group were more likely to be triple-negative breast cancer (61.3%). Patients in the BRCA2 group were also younger at diagnosis (mean age, 41 years) and were more likely to have involvement of the axillary node than the registry group (45.5% vs. 33.5%, p=0.002). The BRCA1 and BRCA2 groups did not show a correlation between tumor size and axillary node involvement.

Conclusion

We report the characteristics of BRCA mutation positive breast cancer patients in the Korean population through multicenter data and nation-wide breast cancer registry study. However, BRCA-mutated breast cancers appear highly complex, and further research on their molecular basis is needed in Korea.

The korean hereditary breast cancer study: review and future perspectives

Most studies related to BRCA mutations have been performed in Western populations, and only a few small studies have been conducted in Korean populations. In 2007, the Korean Hereditary Breast Cancer (KOHBRA) Study was established to obtain evidence for the accurate risk assessment and management of hereditary breast and ovarian cancer (HBOC) in Korea. Between May 2007 and May 2010, the first phase of the KOHBRA Study was performed to estimate the prevalence of BRCA1/2 mutations among patients and their families at risk for HBOC. Between June 2010 and May 2013, the second phase of the KOHBRA Study was performed to identify the clinical characteristics and prognostic indicators of BRCA-related breast cancer and environmental and genetic modifiers of BRCA mutations and to develop a Korean BRCA risk calculator and nationwide genetic counseling network for HBOC. Herein, we review the results of the KOHBRA Study and describe the future perspectives of the study.