The mechanism of BRCA1 participate sporadic breast carcinomas genesis

Objective To elucidate the BRCA1 participated mechanism of genesis and development of sporadic breast cancer through detect the statues of BRCA1 and analysis the relationship with the pathologic and clinic parameters.Methods BRCA1 statues were respectively analyzed in frozen samples or paraffine fixed sporadic breast carcinoma and benign breast tissues by three methods:protein expression by immunohistochemistry(IHC),the methylation of BRCA1 promoter by methylation specific PCR(MSP),gene copy number by interphase fluorescence in situ hybridization(FISH).Results 14.2%(29/204)cases were detected hypermethylation of BRCA1 promoter in sporadic breast cancer.BRCA1 mean copy number in sporadic breast cancer(1.70±0.14)less than those in benign tissues(2.03±0.08,P<0.05),and in sporadic breast cancer with hypermethylation of BRCA1(1.62±0.09)significantly less than in those without hypermethylation(1.84±0.26,P<0.05).The loss copy related to the methylation of BRCA1 promoter.There were significant of 41.1%(88/214)cases no BRCA1 nuclei expression in sporadic breast cancers.Loss expression of BRCA1 had significant correlation with higher histological stages,axillary's lymph nodal metastasis(P<0.01),lower expression of ERα,and overexpression of HER-2 protein(P<0.01).Conclusions There are BRCA1 methylations,loss BRCA1 gene copy and loss protein expression in the sporadic breast cancer,the three statues of BRCA1 is correlated to each other;and the loss expression of BRCA1 protein related to part of pathology and clinic parameters.