Driven by the IgH locus, PAX5-ELN efficiently induced the B-ALL in mice associated with the acquisition of secondary mutations in genes involved in the JAK/STAT and RAS/MAPK pathways, which are recurrently found in B-ALL patients [162] and in other oncogene-induced B-ALL models such as ETV6-RUNX1 [185] and TCF3-PBX1 [186] transgenic mice. This evidence concerns the gene TCF3 and precursor B-cell acute lymphoblastic leukemia.