IMMUNOFLUOROMETRICALLY DETERMINED P53 ACCUMULATION AS A PROGNOSTIC INDICATOR IN ITALIAN BREAST-CANCER PATIENTS

The prognostic value of p53 protein accumulation in breast cancer, esp ecially as detected by methods other than immunohistochemistry, has no t been established unequivocally, A sensitive immunofluorometric assay of p53 protein employing DO-1 and CM-1 antibodies was used in this st udy to assay extracts of 171 breast carcinomas from northern Italy. p5 3 over-expression, demonstrated in 36 (21%) tumours, was associated wi th lack of oestrogen receptor (ER) expression but was not related to p atient age, stage, lymph node status, tumour size, histologic type, gr ade or progesterone receptor (PR) expression status in contingency tab les, An increased risk for cancer relapse of p53-positive patients com pared to p53-negative patients was determined using multivariate Cox r egression analysis, which also showed that p53 protein over expression was an independent predictor of reduced disease-free survival in node -positive and ER+ patients but not in node-negative or ER- individuals . The equivalent analysis for assessing the impact of p53 status on ov erall survival was not statistically significant, possibly reflecting the short patient follow-up. Our results suggest that an immunoassay o f p53 protein, applicable to cytosolic extracts prepared for steroid h ormone receptor analyses, may provide information for breast cancer pr ognosis. (C) 1998 Wiley-Liss, Inc.