PBX1 and acute lymphoblastic leukemia: ALL has been described as usually resulting from protooncogene formation and re-arrangements due to translocations between various chromosome combinations including chromosomes 12 and 21 (ETV6-RUNX1), 4 and 11 (MLL-AF4), 1 and 19 (E2A-PBX1), 9 and 22 (BCR-ABL1), trisomy 4 and 10, ETV6-RUNX1-like, DUX4-rearranged, hyperploidy, hypoploidy, and intra-chromosomal rearrangements of chromosome 21 [7].