PGP and cancer: A recent study reported that curcumin nanoparticles loaded with DOX could more efficiently deliver and localize DOX into P-gp- and MRP-overexpressed cancer cells (e.g., glioblastoma) by inhibiting those efflux transporters, thereby enhancing the anticancer efficacy in the tumor-xenograft model compared to the treatment of DOX solution, while this synergistic effect is the most remarkably exhibited in the treatment of polyethylene glycol-conjugated curcumin nanoparticles loaded with DOX [103].