ERBB2 and neoplasm: In mice, growth of MCF-7/HER2-18 tumours was inhibited by R115777 50 mg/kg (n = 19) and 100 mg/kg (n = 11) by 80.8% (interquartile range 56.4–99.0%; P = 0.001) and 95.9% (68.2–110.1%; P = 0.02), respectively, compared with control tumours (n = 22; Figure 1a and Table 1).