EGF and breast cancer: Indeed, administration of non-toxic doses of chloroquine (i.e., 10 μM) (Fig. 3A), which are effective in blocking the lysosomal-dependent EGF-induced EGF-R degradation {(Fig. 3C) and [28]}, partially prevents the dose- (Fig. 3D) and time-dependent (Fig. 3E, 3F and Fig. S1C) E2-induced ERα degradation in breast cancer cells.