A combination of the statuses of various IHCs is used to describe different molecular subtypes, of which luminal A (ER+ and/or PR+, HER2−, low proliferation marker Ki-67) and luminal B (ER− and/or PR+, HER2+ or HER2− with high Ki-67) are frequently used for characterizing breast tumors [4]. The gene discussed is ERBB2; the disease is breast neoplasm.