For the VCR-resistant Eca109 cell line (Eca109/VCR), co-administration of 5.0 μM OY-103-B resulted in a reversal fold of up to 727.2, superior to the typical third-generation P-gp inhibitor tariquidar, and it reversed tumor drug resistance by inhibiting P-gp. The gene discussed is PGP; the disease is neoplasm.