The role of BRCA1 gene mutations and apoptosis phenomenon in sporadic breast cancer.

BRCA1 tumor suppressor gene encodes an 1863-amino acid gene product that is implicated in many cellular pathways including transcription, cell-cycle checkpoint control, apoptosis and DNA repair. A role of apoptosis and BRCA1 germ-line mutation in breast cancer appearance was investigated in this study by both apoptosis frequency analysis and mutation screening of BRCA1 among breast cancer cases. Blood was obtained from 40 women with node-negative and node-positive ductal breast carcinomas with uniform tumor size. The blood samples from age matched healthy women (n=42) served as control. BRCA1 gene mutations were determined by PCR-RFLP methods. The apoptotic peripheral blood cells were detected by agarose gel electrophoresis. The apoptotic cells were identified in 30% (12/40) of the patients. There were no significant differences in apoptosis frequencies between patients and controls (P > 0.05). Three mutations of BRCA1 gene were identified in apoptosis positive samples from breast cancer women; one Ex20insC and two ExII17delA. Our study implies that apoptosis may be involved not only in sporadic breast carcinoma without BRCA1 mutations, but also in BRCA1-associated breast carcinoma.