Objective The investigators aimed to transfer multidrug resistant (MDR1) gene into hematopoietic cells of human cord blood mononuclear cells (CBMNC) by a retrovirus vector containing a full-length cDNA of human MDR1 gene and explored a secure, stable and efficient method. The authors also attempted to assess the safety, feasibility and functional expression of transferred MDR1 gene into cord blood mononuclear cells in vitro and provided with favorable conditions for protecting bone marrow hematopoietic cel...