C-ERBB-3 PROTEIN EXPRESSION IN DUCTAL CARCINOMA IN-SITU OF THE BREAST

c-erbB-3, A recently identified member of the type I tyrosine kinase r eceptor family, has been shown to be overexpressed in invasive ductal carcinoma of breast. In this study, expression of the c-erbB-3 protein was examined in 57 cases of pure ductal carcinoma in situ of the brea st (DCIS) by immunocytochemical methods. Staining was either absent (1 7 cases), present at levels equivalent to that found in adjacent norma l tissue (20) or greater than in normal tissue (20). In most cases the pattern of staining was cytoplasmic, but in 4 cases with the most int ense reaction there was also focal membrane staining. In the same seri es of cases, c-erbB-2 protein had previously been shown to be overexpr essed in 28 of 57 cases. c-erbB-2 overexpression was correlated with n ormal levels of c-erbB-3, and lack of c-erbB-2 expression was correlat ed with c-erbB-3 overexpression. (C) 1997 Elsevier Science Ltd.