In the human melanoma MDA435/LCC6MDR xenograft, the co-administration of FM04 (28 mg/kg, I.P.)with PTX (12 mg/kg, I.V.)directly modulated P-gp-mediated PTX resistance and caused a 56% (*, p < 0.05) reduction in tumor volume without toxicity or animal death. The gene discussed is PGP; the disease is neoplasm.