We detected the most similar cancer cells and optimal drugs for four subtypes of breast cancer Luminal A, Luminal B, Her2, and Basal Like (triple negative breast cancer, TNBC) in the 1097 patients with breast cancer in TCGA, especially for TNBC in detail, which can be more challenging to treat, without any small molecular inhibitors in clinic currently. The gene discussed is ERBB2; the disease is cancer.