PBX1 and precursor B-cell acute lymphoblastic leukemia: Hyperdiploidy in B-ALL normally conveys a favorable prognosis, but in the present study, the particular pattern of a t(1;19)(q23;p13.3) with TCF3-PBX1 fusion within the context of a complex karyotype (>3 abnormalities) and hyperdiploidy due to extra copies of chromosomes 8, 11 and 22 (confirmed by FISH) plus the presence of a marker chromosome of unknown origin is associated with an unfavorable prognosis in B-ALL [3].