ERBB2 and neoplasm: According to the ASCO/CAP guidelines, a HER2-positive result by IHC is uniform, intense staining of >30 % of invasive tumor cells (3+) and a positive result by ISH is >6 HER2 gene copies per nucleus or a HER2 gene:chromosome enumeration probe 17 (CEP17) signal ratio of >2.2 [18].