EXPRESSION OF P53 PROTEIN HAS NO INDEPENDENT PROGNOSTIC VALUE IN BREAST-CANCER

A series of 392 female breast carcinomas was analysed immunohistochemi cally for expression of p53 protein with special emphasis on the role of p53 as an independent prognostic factor. Altogether, 54.8 per cent of the carcinomas expressed p53 protein, with the mean [standard error (SE)] fraction of positive nuclei being 17.1 per cent (1.2 per cent). Expression of p53 protein was independent of tumour metastasis at dia gnosis, axillary lymph node status, tumour diameter, histological type , tubule formation, proportion of intraductal growth, margin formation , necrosis, DNA ploidy, and S-phase fraction. A high fraction of p53-p ositive nuclei was significantly related to patient age under 70 years , high grade, severe nuclear pleomorphism, dense infiltration of tumou r by lymphocytes, high mitotic index, and high apoptotic index (for al l, P<0.05). Impaired survival probability in the entire cohort (P=0.05 ) and in the axillary lymph node-positive (ANP) tumours (P=0.015) was associated with a fraction of p53-positive nuclei less than 25 per cen t, while in the axillary lymph node-negative (ANN) tumours, expression of p53 had no prognostic value. In multivariate analysis, independent prognostic predictors included axillary lymph node status, tumour dia meter, and mitotic index. In the ANN tumours, tumour diameter, fractio n of p53-positive nuclei, and tumour grade were independent prognostic factors, whereas in the ANP tumours, diameter and mitotic index were the two independent prognostic factors. The results suggest that abnor mal expression of p53 protein is only a weak independent prognostic fa ctor in female breast cancer.