Post-hoc exploratory analysis showed that the most pronounced survival benefit from the addition of trastuzumab was seen in patients with IHC 2+/FISH positive or IHC 3+ tumours (median OS: 16.0 vs. 11.8 months; HR 0.65 (95% CI 051–0.83)), suggesting that higher levels of HER2 overexpression, perhaps more so than amplification, are a prerequisite for trastuzumab efficacy [7]. The gene discussed is ERBB2; the disease is neoplasm.