ERBB2 and breast cancer: Cav-1 is highly expressed in T-DM1-resistant HER-2 (+) breast cancer cells, and T-DM1 fuses with lysosomes intracellularly through Caveolae-mediated endocytosis, while the acidic environment in the lysosomal Cavity weakens the drug efficacy of T-DM1 (Chung et al., 2018; Sung et al., 2018).