As opposed to AID-driven B-cell lymphomagenesis, where the penetrance of the disease is very high20, the discovery that infection-mediated native B-ALL takes place without AID contribution is consistent with the fact that only a minority of healthy newborns harboring a preleukemic clone evolve to overt B-ALL42. This evidence concerns the gene AICDA and precursor B-cell acute lymphoblastic leukemia.