Prognostic value of p53 protein expression in breast carcinomas

A group of 196 ductal infiltrating carcinomas of the breast was examined immunohistochemically for p53. The purpose of this study was to show whether frozen and fixed tissues are equally adequate for detection of p53 and which antibodies should be used to have a prognostic value. Detection was superior on frozen to that on formalin-fixed tissues. It was not possible with any method to improve results on fixed tissues. Detection of p53 was different for each antibody: M 1801 detected 41 cases on frozen tissues, M-240 52 cases, M-421 28 cases. Using all the antisera, and the rabbit antiserum CM1, it was possible to detect 71 cases (36%). The percentage was the same in infiltrating lobular carcinomas but higher (94%) in medullary carcinomas. p53 was associated with high grade and ER-tumours. In formalin-fixed tissues, p53 had no prognostic value. In frozen tissues p53 was not an independent factor of prognosis. However, it was important in sorting out cases with bad prognosis in the ER-carcinomas and in the carcinomas without metastases. The prognostic value was different for each monoclonal antiserum. Positivity with M421 associated with negativity for M240, and positivity only for M1801 sorted out cases with a poor prognosis (67% and 50% deaths at 5 years).