PGP and neoplasm: Indeed,the pharmacological inhibition of hCA XII causes a decrease in theintracellular pH, which elicits a remarkable reduction in the ATPaseactivity of P-gp and consequently in the efflux activity of the transporter.18,25 Therefore, the development of compounds with a dual inhibition ofP-gp and hCA XII could be a useful strategic approach to revert MDRin resistant tumor cells that overexpress both proteins.