The last few years have shown an extraordinary development of laboratory and clinical research in breast cancer. The areas which appear particularly important for possible clinical application are many and diversified. In this review we will update the present knowledge regarding four major issues: 1) biologic and molecular tests of prognostic significance in operable breast cancer patients; 2) detection of breast cancer cells in the bone marrow; 3) the endocrine aspects of breast cancer treatment; and 4) the indication of conservative treatments.