Figure 5.

Expression status of BP1 and BRCA1 in normal and different breast lesions. Consecutive tissue sections from human breast tumors (n=15) with co-existing normal, pre-invasive, and invasive components were immunostained using antibodies for BP1 and BRCA1, and the expression status of BP1 and BRCA1 at the same cell population in two different sections was compared. Distinct BRCA1 expression but no distinct BP1 expression was consistently seen in most normal (A) and hyperplastic (B) cells. BRCA1 expression appeared to decrease with the extent of tumor progression, with no or substantially reduced expression in most in situ (C) and invasive (D) tumor cells, while intense and uniform BP1 immunoreactivity was consistently present.