OVEREXPRESSION OF P53 AND PROGNOSIS IN BREAST-CANCER

Background. Assessment of prognostic markers in breast cancer independ ent of the axillary lymph node status is of major concern for the appl ication of adjuvant treatment regimens. The current treatment decision is based mainly on the axillary lymph node status. Because of improve d screening methods, the number and proportion of patients with node-n egative disease are increasing, which warrants a search for reliable p rognostic parameters. The application of tumor suppressor gene express ion appears to be especially suited as a marker of the progress in mal ignant cellular dedifferentiation. Methods. Tumor tissues of 156 patie nts with primary invasive breast cancer were analyzed immunohistochemi cally for the presence of p53 protein in paraffin-embedded material. T he reaction to monoclonal antibody PAb1801 yielded better results than did reactions to monoclonal antibody DO1 and polyclonal antibody CM-1 . The significance of the immunohistochemical data was compared with a panel of established risk factors. Results. Nuclear accumulation of p 53 protein proved to be an independent marker of dedifferentiation, re gardless of the lymph node status. Tumors showing p53 immunoreactivity were significantly more often related with histological Grade 3 and t he absence of steroid hormone receptors. Kaplan-Meier estimation and m ultivariate analysis of disease-free and overall survival rate corrobo rated the importance of p53 as a prognostic parameter. Conclusion. Ove rexpression of p53 protein emerged as a reliable and independent predi ctor for disease recurrence and reduced survival rates in patients wit h breast cancer.