In contrast to DOX, these studies identified that Dp44mT or DpC markedly decreased Pgp expression (Figure 1d), an effect due to the selective killing of Pgp-expressing cells (Figures 1c,3bii and biii) via lysosomal Pgp-mediated drug sequestration and LMP.5, 6 Consistent with this, Dp44mT and DpC displayed potent activity against Pgp-expressing tumor cells (Figures 3bii and biii).5 These observations form a strong rationale for combining these agents to target Pgp-expressing and non-Pgp-expressing cells. Here, PGP is linked to neoplasm.