PGP and central nervous system cancer: In a rat RG2 glioma model, tesmilifene reduced transendothelial electrical resistance and inhibited key efflux transporters—P-gp/ABCB1, BCRP/ABCG2, and MRP1—resulting in a 2.7-fold increase in fluorescein accumulation and enhanced albumin permeability within tumor tissue [172].