ERBB2 and breast cancer: The addition of trastuzumab to chemotherapy positively affects the natural history of the HER2-overexpressing breast cancer, though many questions about the best dose and schedule (weekly or 3-weekly) of trastuzumab (Gelmon et al, 2001; Carbonell et al, 2002), the best combination and the optimal duration of therapy with trastuzumab need to be addressed.