Subcellular localization of BRCA1 protein in sporadic breast carcinoma with or without allelic loss of BRCA1 gene

The localization of BRCA1 protein was studied in 49 sporadic breast carcino mas for which allelic losses of BRCA1 have been investigated. One group con sisted of 15 breast carcinomas having one allelic loss of BRCA1 and the oth er group of 34 breast carcinomas with no allelic loss of BRCA1. The localiz ation of BRCA1 in the 2 groups was performed using polyclonal antibodies (K -ls; C-20; D-20; I-20) raised against BRCA1 and by comparing frozen and par affin-embedded tissues. We show that no correlation was found between the e xpression of BRCA1 protein and allelic loss of BRCA1. But, the nuclear dete ction of BRCA1 in frozen samples was improved when compared to paraffinized ones.