However, exposure to doxorubicin led to endolysosomal localization of both Pgp-EGFP and doxorubicin in RBE4-MDR1-EGFP cells, indicating that doxorubicin exposure induced the formation of Pgp-containing endolysosomal vesicles in RBE4 cells as previously reported for cancer cells [12]. Here, ABCB1 is linked to cancer.