The aim of this study is to justify an individual therapeutical attitude in breast cancer, related to diversity of breast tumors, aggressiveness grade and metastatic potential. Between January 2000--December 2001, 150 patients were admitted with breast cancer (stage II and III) and underwent surgery in our department. We selected 75 cases in our study. In 51 (68%) cases the first therapeutical method was surgery, in 15 (20%) cases surgery was performed after chemotherapy, in 2 (2.66%) cases after radiotherapy and after chemotherapy and radiotherapy in 7 (9.33%) cases. We evaluated several classical factors and new immunohistochemical markers with an important value for diagnosis, prognosis and therapy: oestrogen and progesterone receptors, c-erb B2, pS2 and p53 proteins, von Willebrand factor. Several factors had a predictive role regarding the response to chemotherapy. These predictive factors will improve the histopathological diagnosis. The oncoproteins and hormonal receptors also will evaluate with more accuracy the metastatic risk and will assure a better therapy decision.