PGP and cancer: Elevated drug efflux pump-related proteins such as P-gp, MRP1, MRP2, and BCRP expression significantly promotes cancer chemoresistance.27 Consistent with the previous report in renal carcinoma cells that reduce the expression of PRKCE lowered MDR1/P-gp, which affects the cancer stem cell potential of sorted side population cells and suppresses proliferation potential, resistance to chemotherapeutics and in vivo tumor formation ability.17 Our identification of the regulatory role of miR-218-5p-PRKCE-MDR1 axis in GBC cells further confirmed its importance.