ERBB2 and neoplasm: The latest ASCO/CAP guidelines update published in 2018 re-classified these tumours into 2 groups: Group 1 (HER2/CEP17 ratio ≥2.0 and HER2 copy number >4.0) remained as HER2 positive but Group 2 (ratio ≥ 2.0 and HER2 gene copy number <4.0) was changed to HER2 negative.