Molecular cloning of t(2;7)(p24.3;p14.2), a novel chromosomal translocation in myelodysplastic syndrome-derived acute myeloid leukemia.

In this study, we report the molecular structure of the breakpoint region in a new chromosomal translocation, t(2;7)(p24.3;p14.2), in a case of acute myeloid leukemia transformed from myelodysplastic syndrome (MDS). An extensive fluorescence in situ hybridization (FISH) analysis showed that NAG (2p24.3) and ELMO1 (7p14.2) were involved at the breakpoints of t(2;7)(p24.3;p14.2). Furthermore, we detected a novel chimeric transcript consisting of NAG and ELMO1. Interestingly, this transcript encoded a truncated molecular form of 3'ELMO1 as the result of a frameshift caused by the chromosomal translocation. Although this study does not provide direct evidence that a defect in NAG-ELMO1 plays a role in the pathogenesis or the leukemic change in MDS, it does suggest that defects in NAG-ELMO1 potentially contributed to the leukemic progression in this case.