Value of c-erbB-2 and p53 oncoprotein co-overexpression in human breast cancer.

p53 and c-erbB-2 protein expression was immunohistochemically examined in a consecutive series of 49 primary breast cancer patients with a 10-year follow-up. The study was performed on paraffin sections using the monoclonal antibodies DO7 and CBE1; the former recognizes both the wild-type and the mutant p53 forms, the latter recognizes the external domain of the transmembrane c-erbB-2 protein. Positive staining was expressed in 12.2% and 16.3% of cases for p53 and c-erbB-2 proteins, respectively. The results were related to clinicopathological parameters by the chi 2 test. A significant correlation was found between positive c-erbB-2 immunostaining and poor survival (P = 0.04) and between p53 and c-erbB-2 overexpression (P = 0.003); this co-overexpression correlated well with a poor clinical outcome (P = 0.040). From our results, we may speculate that simultaneous expression of p53 and c-erbB-2 oncoproteins could be a critical event in breast tumor progression, and therefore, of prognostic value to identify patients at high risk.