Localization of human BRCA1 and BRCA2 in non-inherited colorectal carcinomas and matched normal mucosas.

We characterized the expression of BRCA1 and BRCA2 in 38 sporadic colorectal carcinomas and matched normal mucosas with 9 anti-BRCA1 antibodies and 4 anti-BRCA2 antibodies, raised against several different epitopes, using immunohistochemical technique. We demonstrated an increased BRCA1 and BRCA2 staining in the apical cell pole of epithelial malignant cells and we also revealed a significant increase in BRCA1 and BRCA2 nuclear foci in tumor colorectal specimens in comparison with corresponding normal tissues. These increases in BRCA1 and BRCA2 expression may be explained by the fact that colorectal tissue is subject to very active proliferation and differentiation.