CD19 and leukemia: This model provided a spectrum of diseases ranging from AML to B-ALLs, including pre-B and pro-B ALLs and B/M-MPAL, most of which expressed Hoxa9 and Meis1. Lin et al. also developed a valuable model of MLL-AF4-mediated leukemia wherein MLL-mAf4 was retrovirally transduced into human HSPCs and transplanted into immuno-compromised mice, which developed pro-B ALL with the CD19+ CD10− CD34+ immunophenotype17.