BrCA can be intrinsically clustered into five subtypes including Luminal A (L-A), Luminal B (L-B), Her2-overexpressing (Her2-oe), triple-negative (TNBC) and normal-like breast cancer based on the gene expression profile [3], while the first four subtypes are commonly used in studies [4]. The gene discussed is ERBB2; the disease is breast carcinoma.