Looking back to the recommendation for HER2 classification on the 2013 version of the HER2 testing guidelines, although extra HER2 testing was suggested, cases with a HER2/CEP17 ratio ≥2.0 and an average HER2 copy number <4.0 per tumor cell (called group 2 by 2018 guideline) were automatically classified as HER2 positive regardless of the HER2 IHC results (including IHC2+ which should be further re-tested by FISH, but where IHC3+, 1+, or 0 would not be, usually). The gene discussed is ERBB2; the disease is neoplasm.