The 5-10% of breast cancers (BC) are hereditary, and BRCA1/2 are causative in 25% of those inherited. It was aimed to examine the BRCA1/2 genotype-BC phenotype relationship. In 170 female patients with BC, BRCA1/2 genes were investigated using Next Generation Sequencing. Demographic and clinicopathological characteristics of the patients and correlations of pedigree analysis with BRCA1/2 mutation status were analysed. BRCA1/2 carriage was found to be 9.4%. When the patients were grouped as ≤ 40 and > 40 according to the age at diagnosis of BC, the tumour grade was higher in the ≤ 40 groups. In the study, BRCA1/2 carriage and tumour grade were higher in patients with triple-negative breast cancers (TNBC). The risk of TNBC was 5.560 times higher in BRCA1/2 carriers than in non-carriers. There is a significant relationship between BRCA1/2 carrier and BC hormone receptor negativity, tumour grade, and BC diagnosis age.
Keywords: BRCA1; BRCA2.; oestrogen receptor; progesterone receptor; triple-negative; breast cancer.