Through the use of immunohistochemistry (IHC) staining and fluorescence in situ hybridization (FISH) analyses, the main molecular subtypes of breast cancer were identified, as follows: luminal A (Hormone receptor-positive/Human Epidermal Growth factor Receptor-2 negative; HR+/HER2−), luminal B (HR+/HER2+and HR+/HER2−), basal-like (HR−/HER2−), and HER2-enriched (HR−/HER2 +) [9]. The gene discussed is ERBB2; the disease is breast cancer.