HER2-L755S expressing cells exhibit hyperactivation of MAPK and PI3K/AKT/mTOR pathways. (a) Western blotting showing the expression of HER2, EGFR, AKT, p70S6K, MEK1/2 and p42/44 MAPK in indicated MCF10A cells. β-actin was used as a loading control. (b and c) Western blotting showing the expression of HER2, EGFR, AKT, p70S6K, MEK1/2 and p42/44 MAPK in indicated MCF10A cells treated by lapatinib (b) and neratinib (c) at indicated concentrations for 4 h. β-actin was used as a loading control.