In conclusion, we have identified several proteins that were differentially expressed following exposure to clinically relevant concentrations of different HER2-inhibitors drug treatments in HER2-overexpressing breast cancer cell lines, lapatinib, neratinib or afatinib in BT474 and in response to neratinib treatment in two other cell lines (HCC1954 and SKBR3). Here, ERBB2 is linked to breast cancer.