Abnormal p53 immunoreactivity and prognosis in node-negative breast carcinomas with long-term follow-up.

The expression of the p53 gene product was investigated immunocytochemically in a retrospective series of 164 formalin-fixed paraffin-embedded invasive breast carcinomas with pathologically proven negative lymph nodes. Overall, 78 tumors (48%) showed a variable degree of p53 immunoreactivity. Among these, 38 cases were low expressors (1-10% p53 immunoreactive tumor cells), 21 moderate expressors (10-50% immunoreactive cells) and 19 high expressors (> 50% immunoreactive cells). Abnormal p53 expression correlated significantly with tumor size, histological and nuclear grade, DNA ploidy, mitotic rate and proliferation index, and with the lack of estrogen receptors. Disease-free and adjusted survival analysis of the 124 node-negative patients with long term (more than 10 years) follow-up, however, did not reveal an independent prognostic role for p53 expression. These data suggest that the evaluation of p53 immunoreactivity may only play a role in a multiparametric prognostic assessment of node-negative breast carcinoma.