found that berberine significantly downregulated the expression of P-gp/ABCB1 and MRP1/ABCC1 in a xenograft model of drug-resistant cell lines, which reduced the efflux of DOX, increased the uptake of DOX by tumor tissues and increased the concentration and retention of DOX in tumor cells; these findings provide practical and feasible new ideas for tumor therapy (66). The gene discussed is PGP; the disease is neoplasm.