Epidemiological and clinicopathological characteristics of BRCA-positive and BRCA-negative breast cancer patients in Greece.

Purpose: BRCA mutation carriers can benefit from targeted clinical interventions. On the other hand, families with evident aggregation of breast cancer (BC) cases and a BRCA-negative genetic test can still be considered as of elevated risk, since the underlying genetic factor remains unidentified. In the present study, we compared clinical and demographic characteristics between BRCA1 mutation carriers (BRCA1mut) and non-carriers (non-BRCA1) in a Greek group of BC patients (n=321).

Methods: Data were collected and analyzed from 321 women with BC, with 131 patients screened for pathogenic mutations in the high-penetrant genes BRCA1 and BRCA2. Collected data included demographics, pedigrees, tumor histopathology and immunohistochemistry findings.

Results: In BRCA1mut patients, their mothers and grand- mothers were diagnosed at a younger age compared to non-BRCA1-carriers. Additionally, BRCA1mut patients were diagnosed with mainly estrogen receptor (ER) negative (p<0.001), Her-2 negative (p<0.05) and triple negative (p<0.01) tumors. The youngest generation was diagnosed with familial breast cancer (FBC) 9.7 years earlier than their mothers (p<0.001). Age at BC diagnosis negatively correlated with the nuclear grade of breast tumors (r=-0.3, p<0.05). Among parous individuals, the number of full-term pregnancies significantly correlated with the age at BC onset (r=0.19, p<0.05).

Conclusion: Despite their similarities, FBC cases with identified BRCA1 mutations exhibit a clearly distinct profile. We have identified an anticipation effect in FBC patients, with significantly reduced age at diagnosis in younger generations. Increased parity seems to prevent early BC onset. This is the first study comparing clinical and demographic characteristics of FBC BRCA1mut and non-carriers in a Greek cohort.