The PAX5 gene is a paired box (Pax) family member, a domain of 9 highly conserved DNA-binding domains involved in organogenesis and brain development.[37–40] PAX5 plays a crucial role in embryonic development and cell differentiation.[41] It is expressed from the pro-B to the mature B-cell stage in the bone marrow and is downregulated in the final stage of differentiation into plasma cells.[42] PAX5 is the primary target of genetic alterations in B-ALL, with more than a third of patients having mutations that result in downregulation and a defect in DNA-binding activity and expression. Here, PAX5 is linked to precursor B-cell acute lymphoblastic leukemia.