Fusion AML1 transcript in a radiation-associated leukemia results in a truncated inhibitory AML1 protein

AML1 is a transcription factor that is essential for normal hematopoietic d evelopment. It is the mast frequent target for translocations in acute leuk emia. Recently, fluorescence in situ hybridization was used to identify a n ovel syndrome of radiation-associated secondary acute myelogenous leukemia that had AML1 translocations. Using polymerase chain reaction, the AML1 fus ion transcript was isolated from the patient who had a t(19;21) radiation-a ssociated leukemia. The AML1 gene is fused out of frame to chromosome 19 se quences, resulting in a truncated AML protein bearing the DNA binding domai n but not the transcriptional activation domain. This fusion AML1 protein f unctions as an inhibitor of the normal AML1 protein. (Blood. 2001;97:2168-2 170) (C) 2001 by The American Society of Hematology.