We analyzed the impact of the following factors on LFS: leukemia immunophenotype (BCP vs. T-cell immunophenotype), risk-group allocation at relapse (SR vs. HR), MRD before SCT (<0.01% vs. ≥0.01%), conditioning regimen (TBI-based vs. chemotherapy-based), CD34+ cell dose (above/below the mean), grade 1 and 2 aGVHD, and any-grade cGVHD. This evidence concerns the gene CD34 and leukemia.