ERBB2 and breast carcinoma: On the contrary, with the exception of JIMT-1 (cell line with acquired resistance to anti-HER2 therapy; ref. 40), HER2+ breast cancer cell lines showed low to negligible reduction of cell proliferation after eCF506 treatment (GI50 > 1.8 μmol/L), which agrees with the expected minor role played by SRC in HER2+ breast cancer cells before becoming resistant to trastuzumab (41).