Associations of pathogenic mutations responsible for breast cancer risk with histology and immunohistochemistry in Romanian population

Introduction: Breast cancer is the most common cancer in women worldwide, and Romania makes no exception from this trend. Genetic screening for Hereditary Breast and Ovarian Cancer began to be used on a larger scale after the introduction of Next Generation Sequencing. The aim of this study was to assess the association of deleterious mutations responsible for breast cancer with histopathological and immunohistochemical prognostic factors and to identify some genetic variants in the BRCA1 and BRCA2 genes. Method: 80 patients with breast cancer and negative genetic test or pathogenic variants on BRCA1/2, TP53, PALB2, CHEK2, ATM genes were included. All the cases had a prior histological diagnosis and complete immunohistochemical features. The genetic testing was conducted through a multigene panel. Results: 65% of patients had a deleterious mutation on BRCA genes. In 97.5% of cases the histology was invasive ductal carcinoma. Significant differences were identified between BRCA1 group and negative mutation group regarding estrogen receptor (ER) (p=0.0051), progesterone receptor (PR) (p=0.0004) and Ki67 (p=0.001). Seven breast cancer patients had BRCA1 c.3607C>T variant, which was statistically significantly associated with triple- negative breast cancer (p A variant in 3 cases and the c.9371A>T variant in 3 cases. Discussion and conclusion: Our study confirmed the association of BRCA1 mutations with negative ER, PR or triple negative breast cancer (TNBC). Description of BRCA1 c.3607C>T mutation for the first time in Romanian population and its association with TNBC will need further investigation