PBX1 has been largely described in acute lymphoblastic leukemia; notably, it has been suggested that, in complex with MEIS2, PBX1 is involved in transcriptional regulation mediated by KLF4, which has been previously shown by us as specifically overexpressed in t(4;14) patients [24, 25]. The gene discussed is KLF4; the disease is acute lymphoblastic leukemia.