Analysis of BRCA1/2 variants of unknown significance in the prospective Korean Hereditary Breast Cancer study

Deleterious and ethnic-related BRCA1/2 mutations in tissue and blood of Egyptian colorectal cancer patients and its correlation with human papillomavirus

This study aimed to identify BRCA1/2 mutational patterns in the tissue and blood of Egyptian colorectal cancer (CRC) patients and to study the possible correlation of this mutational pattern with Human papillomavirus (HPV) infection. Eighty-two colonoscopic biopsies and forty-six blood samples were collected from Egyptian CRC patients, as well as blood samples of age and sex-matched healthy controls (n = 43) were enrolled. The libraries were performed using Qiaseq Human BRCA1 and BRCA2 targeted DNA panel and sequenced via Ion proton sequencer. Also, the CRC tissues were subjected to conventional PCR targeting the HPV Late 1 (L1) region. Our analysis revealed that the BRCA-DNA damage pathway had been altered in more than 65% of the CRC patients. Comparing tissue and blood samples from CRC patients, 25 somatic mutations were found exclusively in tissue, while 41 germline mutations were found exclusively in blood. Additionally, we identified 23 shared BRCA1/2 pathogenic (PVs) mutations in both blood and tissue samples, with a significantly higher frequency in blood samples compared to tissue samples. The most affected exon in BRCA1 was exon 10, while the most affected exons in BRCA2 were 11, 14, 18, 24, and 27 exons. Notably, we revealed an ethnic-related cluster of polymorphism variants in our population closely related to South Asian and African ethnicities. Novel PVs were identified and submitted to the ClinVar database. HPV was found in 23.8% of the CRC tissues, and 54% of HPV-positive cases had somatic BRCA1/2 PVs. The results of this research point to a possible connection between infection with HPV and BRCA1/2 mutations in the occurrence of colorectal cancer in the Egyptian population, which has a mixed ethnic background. Our data also indicate that liquid biopsy (blood samples) may be more representative than tissue samples for detecting BRCA1/2 mutations. These findings may have implications for cancer screening and the development of personalized, targeted therapies, such as PARP inhibitors, which can effectively target BRCA1/2 mutations.

Landscape of germline BRCA1/BRCA2 variants in breast and ovarian cancer in Peru

Background

There is an increasing amount of data from Latin America on the characterization of BRCA variants; however, there is limited information from Peru. We conducted a retrospective study to describe germline pathogenic/likely pathogenic(P/LP) variants and variants of uncertain/unknown significance (VUS) in the BRCA1 and BRCA2 genes in Peru, in patients with breast and ovarian cancer, candidates for treatment with poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors.

Methods

The patients were evaluated during the period 2019-2021. Genomic DNA was isolated from peripheral blood samples and targeted sequencing was performed using the Ampliseq BRCA panel. Genetic variant interpretation was carried out in accordance with the recommendations of the American College of Medical Genetics and ClinVar. During this period, 525 patients (143 with breast cancer and 382 with ovarian cancer) were studied.

Results

We found that 14.7% (21/143) of breast cancer patients and 20.7% (79/382) of ovarian cancer patients were carriers of P/LP variants in BRCA1/2. The most frequent pathogenic variants detected in BRCA1 were c.2105dupT (BIC: 2224insT, n=12, 18.75%), c.68_69delAG (BIC: 185delAG, n=6, 9.38%), c.140G>T and c.815_824dupAGCCATGTGG (n=5, 7.81%), while in BRCA2 were c.8023A>G (n=6, 16.67%), c.6024dupG (BIC: 6252insG, n=4, 11.11%), and c.9235delG (BIC: 9463delG, n=3, 8.33%). Regarding VUS, we found that 6.99% (10/143) of breast cancer patients and 7.33% (28/382) of ovarian cancer patients were carriers of a VUS in BRCA1/2. For BRCA1, the most frequent VUS was c.93C>G (n=2), and for BRCA2, c.5465A>T (n=4), c.3101T>C (n=3), c.205C>A and c.437T>C (n=2).

Conclusion

We found a frequency of 14.7% germline mutations in breast cancer patients and 20.7% in ovarian cancer patients. The most recurrent mutations were BRCA1 c.2105dupT and BRCA2 c.8023A>G. We found that BRCA2 c.8023A>G, c.6024dupG, and c.9235delG were not previously reported in Peruvian patients. BRCA1 c.2344dupA is a novel mutation that has not been previously reported in any database. The frequency of VUS in our cohort was 7.2%.

Clinical risk management of breast, ovarian, pancreatic, and prostatic cancers for BRCA1/2 variant carriers in Japan

Opportunities for genetic counseling and germline BRCA1/2 (BRCA) testing are increasing in Japan owing to cancer genomic profiling testing and companion diagnostics being covered by national health insurance for patients with BRCA-related cancers. These tests are useful not only to judge whether platinum agents and PARP inhibitors are indicated but also to reveal an autosomal-dominant inherited cancer syndrome: hereditary breast and ovarian cancer. In individuals with germline BRCA variants, risk of cancers of the breast, ovary, pancreas, and prostate is significantly increased at various ages of onset, but the stomach, uterus, biliary tract, and skin might also be at risk. For women with pathogenic BRCA variants, breast awareness and image analyses should be initiated in their 20s, and risk-reducing procedures such as mastectomy are recommended starting in their 30s, with salpingo-oophorectomy in their late 30s. For male BRCA pathogenic variant carriers, prostatic surveillance should be applied using serum prostate-specific antigen starting in their 40s. For both sexes, image examinations ideally using endoscopic ultrasound and magnetic resonance cholangiopancreatography and blood testing should begin in their 50s for pancreatic surveillance. Homologous recombination pathway-associated genes are also causative candidates. Variant pathogenicity needs to be evaluated every 6-12 months when results are uncertain for clinical significance. Genetic counseling needs to be offered to the blood relatives of the pathogenic variant carriers with suitable timing. We review the recommended cross-organ BRCA risk management in Japan.

Mainstream genetic testing for high-grade ovarian, tubal and peritoneal cancers: A tertiary referral centre experience

BACKGROUND

Fifteen percent of ovarian, tubal, and peritoneal (OTP) invasive epithelial cancers are linked to an underlying heritable pathogenic variant (PV) in the BRCA1/2 cancer susceptibility genes. Identifying a PV has management implications for an affected individual and relatives. Cancer team-facilitated genetic testing (mainstreaming) aims to provide equitable systematic access to genetic testing for appropriate patients.

AIM

To evaluate a multi-disciplinary team (MDT)-led mainstream germline genetic testing program for OTP cancer at a tertiary referral centre.

MATERIALS AND METHODS

We conducted a retrospective review of our MDT-led mainstream genetic testing program initiated in June 2017. We included all patients diagnosed with OTP cancer registered with the hospital gynaecological oncology MDT from program initiation to December 2020. Patients were considered eligible for testing if they were diagnosed with a high-grade epithelial OTP AND ≤70 years, OR if >70 with a first/second degree relative with breast and/or ovarian cancer OR Jewish ancestry.

RESULTS

Of 205 women diagnosed with high-grade epithelial OTP cancer, 140 were eligible for mainstreaming. Eight-five percent were mainstreamed, with the gynae-oncologists facilitating 64.5% of tests. The overall PV detection rate in BRCA1/2 was 10.1% (BRCA1 n = 9, BRCA2 n = 3). The median turnaround time (TAT) was 44.5 days (range 16-118). All women with PV were referred to the Familial Cancer Service for further assessment and five (of six eligible; 83%) were subsequently treated with polyadenosine diphosphate ribose polymerase inhibitors. Cascade testing was undertaken in 75% of families with a mean of three relatives tested per proband.

CONCLUSION

Mainstreamed genetic testing is feasible, with an acceptable TAT, ensuring adequate opportunity to inform treatment decisions. Tumour testing and inclusion of moderate-risk cancer predisposition genes in mainstreaming represent potential pathways that will require further exploration.

Assessing the pathogenicity of BRCA1/2 variants of unknown significance: Relevance and challenges for breast cancer precision medicine

Introduction

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide. Pathogenic variants in BRCA1 and BRCA2 genes account for approximately 50% of all hereditary BC, with 60-80% of patients characterized by Triple Negative Breast Cancer (TNBC) at an early stage phenotype. The identification of a pathogenic BRCA1/2 variant has important and expanding roles in risk-reducing surgeries, treatment planning, and familial surveillance. Otherwise, finding unclassified Variants of Unknown Significance (VUS) limits the clinical utility of the molecular test, leading to an "imprecise medicine".

Methods

We reported the explanatory example of the BRCA1 c.5057A>C, p.(His1686Pro) VUS identified in a patient with TNBC. We integrated data from family history and clinic-pathological evaluations, genetic analyses, and bioinformatics in silico investigations to evaluate the VUS classification.

Results

Our evaluation posed evidences for the pathogenicity significance of the investigated VUS: 1) association of the BRCA1 variant to cancer-affected members of the family; 2) absence of another high-risk mutation; 3) multiple indirect evidences derived from gene and protein structural analysis.

Discussion

In line with the ongoing efforts to uncertain variants classification, we speculated about the relevance of an in-depth assessment of pathogenicity of BRCA1/2 VUS for a personalized management of patients with BC. We underlined that the efficient integration of clinical data with the widest number of supporting molecular evidences should be adopted for the proper management of patients, with the final aim of effectively guide the best prognostic and therapeutic paths.

Comprehensive clinical characterization of patients with BRCA1: c.5017_5019del germline variant

Purpose

We provide evidence for the reclassification of the BRCA1:c.5017_5019del variant by presenting the clinicopathological characteristics, clinical outcomes, and family history of breast or ovarian cancer in 17 patients with this variant.

Methods

This study included breast or ovarian cancer patients tested for BRCA1/2 genes between January 2008 and June 2020 at 10 medical centers in Korea. We retrospectively reviewed 17 probands from 15 families who had the BRCA1:c.5017_5019del variant according to the electronic medical records.

Results

We present 10 breast cancer patients and 7 ovarian cancer patients from 15 families identified as having BRCA1:c.5017_5019del and a total of 19 cases of breast cancer and 14 cases of ovarian cancer in these families. The ratio of breast-to-ovarian cancer was 1.3:1. Breast cancer patients with this variant showed a rich family history of breast or ovarian cancer, 8 patients (80.0%). The mean age at diagnosis was 45.4 years and 6 patients (60.0%) were categorized into hormone-receptor-negative breast cancer. Also, the ovarian cancer patients with this variant showed strong family histories of breast and/or ovarian cancer in 4 patients (57.1%).

Conclusion

We presented clinical evidence for the reclassification of BRCA1:c.5017_5019del as a likely pathogenic variant (LPV). Reclassification as LPV could result in the prophylactic treatment and medical surveillance of probands, family testing recommendations, and appropriate genetic counseling of their families.

Germline variants in cancer-predisposing genes in pancreatic cancer patients with a family history of cancer

BACKGROUND

Our phase II trial (FABRIC study) failed to verify the efficacy of gemcitabine plus oxaliplatin (GEMOX) in patients with pancreatic ductal adenocarcinoma (PDAC) with a familial or personal history of pancreatic, breast, ovarian or prostate cancer, which suggested that a family and personal history may be insufficient to determine response to platinum-based chemotherapy.

METHODS

This ancillary analysis aimed to investigate the prevalence of germline variants of homologous recombination repair (HRR)-related genes and clarify the association of germline variants with the efficacy of GEMOX and patient outcome in PDAC patients. Of 45 patients enrolled in FABRIC study, 27 patients were registered in this ancillary analysis.

RESULTS

Of the identified variants in HRR-related genes, one variant was considered pathogenic and eight variants in six patients (22%) were variants of unknown significance (VUS). Objective response to GEMOX was achieved by 43% of the seven patients and tended to be higher than that of patients without such variants (25%). Pathogenic/VUS variant in HRR-related genes was an independent favorable factor for progression-free survival (hazard ratio, 0.322; P = 0.047) and overall survival (hazard ratio, 0.195; P = 0.023) in multivariable analysis.

CONCLUSIONS

The prevalence of germline variants in PDAC patients was very low even among patients with a familial/personal history of pancreatic, breast, ovarian or prostate cancer. Patients with one or more germline variants in HRR-related genes classified as pathogenic or VUS may have the potential to obtain better response to GEMOX and have better outcomes.