Expression of many genes associated with human B-ALL was significantly altered between preleukemic and leukemic BCP cells (Supplementary Table 2A, B), including down-regulation of Pax5, Blk, Cdkn2a, Igll1, Tcf3, and Vpreb1. The reduced expression of Pax5 was consistent with the observed down-regulation of several Pax5 target genes in leukemic cells, including Ebf1, Bst1, Cd19, Cd79a, Ccnd3, Vpreb3, and Nedd9 [40]. This evidence concerns the gene BLK and precursor B-cell acute lymphoblastic leukemia.