ERBB2 and breast cancer: Triple‐negative breast cancer (TNBC) is a cancer without estrogen receptors, progesterone receptors, and excess HER2 protein, and includes three common features: (a) more aggressive and poorer prognosis than other types of breast cancer; (b) be higher grade than other types of breast cancer; and (c) usually be like ‘basal‐like’ [2].