Molecular profiling of BRCA1 and BRCA2 genes in Turkish patients with early-onset breast cancer

Abstract

Abstract Background Early-onset breast cancer (EOBC) is a specific condition that affects women under the age of 45. BRCA pathogenic/likely pathogenic (P/LP) germline variants have been demonstrated to be harbored in a subgroup of EOBC individuals, and BRCA-positive genetic result offers an option to ensure more specified therapeutic implications. Establishing comprehensive BRCA1/2 genetic testing, including both the detection of small-scale mutations and large genomic rearrangements (LGRs), is needed for risk assessment and clinical management. In this study, we described a Turkish EOBC cohort along with their clinico-pathological characteristics and BRCA1/2 mutational profiles. A total of 67 unrelated patients were enrolled. Both next-generation sequencing (NGS)-based gene panel and multiplex ligation-dependent probe amplification (MLPA) were performed for BRCA1/2 variant identification. Patients' family medical history and hormone receptor status of the tumors were also recorded. Results 14 (20.90%) patients were found to carry BRCA P/LP germline variants. (Nine were BRCA2-positive, and five were BRCA1-positive.) Two novel BRCA2 variants were detected. No significant differences were found between BRCA-positive vs. BRCA-negative or BRCA1-positive vs. BRCA2-positive for hormonal status and family history. Conclusions BRCA1/2 genes represent a predominant part of the genetic landscape of EOBC. Our results expand the spectrum of BRCA1/2 variants and provide knowledge of the BRCA1/2 variant prevalence in our cohort.

Keywords

• Early-onset breast cancer
• BRCA1
• BRCA2
• Large genomic rearrangement