PAX5 and precursor B-cell acute lymphoblastic leukemia: Somewhat like germline RUNX1 and CEBPA-driven HM, and even more so, in germline PAX5-driven B-ALL, the WT allele of PAX5 is almost always deleted or mutated in some way to abrogate PAX5 activity from this allele, in addition to the perturbation due to the inherited germline variant allele (119).