In support of this, recent studies have demonstrated that CPZ induces G2/M cell cycle arrest [40,41], promotes apoptosis via mitochondrial and lysosomal pathways [42], modulates autophagy, increases reactive oxygen species (ROS) production [43,44], and inhibits P-glycoprotein (P-gp)-mediated drug efflux in various cancer types [45,46]. Here, PGP is linked to cancer.