The authors subtyped breast tumors into HER2-negative and HER2-positive luminal tumors, HER2-positive ER-negative tumors, tumors with the core basal phenotype (“basal-like”) and tumors that lacked expression of the estrogen, progesterone, and HER2 receptors and also cytokeratin 5/6 and EGFR (“triple-negative tumors that are not basal-like”). Here, ERBB2 is linked to breast neoplasm.