To understand the impact that the downregulation of GnT-III exerts on the drug resistance of K562/ADR cells, we carried out a transfection approach to the overexpression of GnT-III in both K562 and K562/ADR cells via viral infection encapsulating the CSIV-TRE-RfA-CMV-KT-GnT-III plasmid and used FACSAria II to establish stable K562-GnT-III and K562/ADR-GnT-III cell lines after sorting. The gene discussed is RPA1; the disease is viral infectious disease.