ERBB2 and neoplasm: Unlike Group 1 and Group 3, Group 2, defined as a HER2/CEP17 ratio ≥2.0 with an average HER2 copy number <4.0 signals per cell with IHC score of 2+, was re-classified from HER2 positive4,19 to HER2 negative.3 This change was based on the lack of substantive evidence for the efficacy of HER2-targeted therapy in such tumours in terms of survival benefit.3,20 These tumours are rare.