Based on cytogenetic and molecular analyses, B-cell precursor acute lymphoblastic leukemia (B-ALL) carries hyperdiploidy, hypodiploidy, translocations t(12;21)[ETV6-RUNX1], t(1;19)[TCF3-PBX1], t(9;22)[BCR-ABL1] and rearrangement of the MLL gene. This evidence concerns the gene TCF3 and acute lymphoblastic leukemia.