Prognosis and prediction of response in breast cancer: the current role ofthe main biological markers

In the medical literature there are frequently conflicting reports on the u tility of biological tumour markers available in the clinical management of breast cancer. In this review we analyse current information on the relati onships between the most widely investigated breast cancer biological marke rs including oestrogen and progesterone receptors, p53, Bcl-2, c-erbB-2, cy clin expression, proliferative activity, DNA ploidy and the urokinase plasm inogen activation system, as well as their relevance to prognosis and respo nse to clinical treatment. By biological prognostic indicator, we mean a ma rker that correlates with survival and disease-free survival; the term pred ictor marker indicates a marker that is capable of predicting tumour sensit ivity or resistance to various therapies. Similarly to other authors' exper iences, our analysis suggests that oestrogen receptors are weak prognostic indicators and good predictors of response to endocrine therapy. Furthermor e, there are consistent data suggesting that proliferation indices are good indicators of prognosis, and that they are directly related to response to chemotherapy and closely related to response to hormonotherapy. On the con trary, there is no evidence or conflicting data for all of the other biolog ical markers. These should be considered in the context of randomized trial s in order to precisely define their prognostic and predictive roles. p53 a nd c-erbB-2 seem to be the most promising factors, but their use in routine practice still needs validation.