Among the HER2 status discordant cases (Table 4), except one case with input error, the majority (14/19) were attributed to IHC discordances including 5 cytoplasmic staining cases and 2 foci strong staining (<10% of tumor) cases misdiagnosed as HER2-overexpressed (IHC 2+/3+) in local laboratories. The gene discussed is ERBB2; the disease is neoplasm.