The role of chromosome translocations in leukemogenesis.

Certain chromosome abnormalities, especially translocations, are specifically associated with particular subtypes of leukemia, lymphoma, and sarcomas. This review describes the translocations involving the AML1(CBFA2) gene on 21q22, the MLL gene on 11q23, and the TEL(ETV6) gene on 12p13. Abnormalities of these genes account for a large proportion of patients with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Cloning of translocation breakpoints results in unique diagnostic tools for fluorescence in situ hybridization (FISH) and molecular analysis of leukemic cells. Recent advances in understanding the alterations in the function of the fusion genes as compared with normal genes provide insights regarding new therapeutic strategies, which should lead to improved clinical responses with less toxicity.