According to the gene expression profile using Prosigna Breast Cancer Prognostic Gene Signature Assay, there are five intrinsic subtypes: luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) enriched, basal-like/triple-negative breast cancer (TNBC), and claudin-low [3,4,5,6]. The gene discussed is ERBB2; the disease is breast cancer.