ERBB2 and breast cancer: Slamon et al (1987) established HER2 as a poor prognostic marker for survival in breast cancer and developed a monoclonal antibody, trastuzumab, targeted to HER2, as a novel therapy for breast cancer patients. More recently, randomised trials in early breast cancer have shown the clinical benefit of trastuzumab after chemotherapy with significant overall survival benefit over chemotherapy alone (Romond et al, 2005; Slamon et al, 2006; Smith et al, 2007).