When quinine was used as a P-gp inhibitor, PLDQ increased the cellular accumulation of DOX and reduced tumor volume by 25% in mice with xenografted HT29-MDR1 positive cells (i.e., P-gp overexpressed HT29 colon cancer cells) compared with PLD (without quinine) [88]. The gene discussed is PGP; the disease is malignant colon neoplasm.