PBX1 and acute lymphoblastic leukemia: In BCP-ALL, common genetic subgroups include ALL with high hyperploidy (a minimum gain of five chromosomes), hypoploidy (less than 44 chromosomes), t(1;19) encoding E2A-PBX1, t(12;21) encoding ETV6-RUNX1, ALL with rearranged KMT2A (MLL) to a range of partners, t(9;22) or Philadelphia-chromosome positive (Ph+) ALL encoding BCR-ABL1 and a subtype called Ph-like ALL having similar gene expression profile as Ph+ ALL but no BCR-ABL1.