The therapeutic result of the free Dox group and EV@Dox–EPT1 were compared with the 808 nm laser irradiation group and it was noted that EV@Dox–EPT1 caused significantly more cytotoxicity in cancer cells under 808 nm laser irradiation than the free Dox group and produced synergistic effects with photochemistry. This evidence concerns the gene SELENOI and cancer.