ERBB2 and breast carcinoma: As preclinical models of acquired resistance to anti-HER2 drugs, we developed a panel of resistant HER2+ breast cancer cells (SK) with long-term (12 months) and high drug concentration exposure of trastuzumab (SKTR), lapatinib (SKLR) and lapatinib plus trastuzumab (SKLTR) (S1 Fig), following Nahta R et al. methodology [31].