There are more luminal B‐like subtype and non‐luminal‐like subtypes (i.e., normal‐like, HER2 enriched and basal‐like) among grade III ER+HER2− breast cancer patients than those with grade I/II tumors (Fig. 5A), indicating that high‐grade tumors are heterogeneous. The gene discussed is ERBB2; the disease is breast carcinoma.