In accordance with the expression status of ER, PR and HER2, BC can be categorized into four subtypes: luminal A (ER+ or PR+/HER2-), luminal B (ER+ or PR+/HER2+), HER2 positive (HER2+), and triple-negative BC (TNBC, ER-/PR-/HER2-) [29]. Here, ERBB2 is linked to breast cancer.