MUC20 and neoplasm: To further confirm the effect and mechanism of MUC20 in decreasing PI resistance in MM in vivo, xenograft tumor mouse models were established by subcutaneously injecting PI-resistant KAS-6/1 and U266 cells into the right dorsal flanks of nude mice, which was followed by intraperitoneal injection of PI (CFZ), elesclomol, TTM, and lentivirus containing a lentiviral vector carrying the MUC20/MET/CDKN2A genes.