Low frequency of rearrangements of the homeobox gene HOXA9/t(7;11) in adult acute myeloid leukemia.

Translocation (7;11)(p15;p15) is uncommon in acute myeloid leukemia (AML) and may have a predilection to occur in Asian patients. It results in a reciprocal fusion of the homeobox gene HOXA9 and the nucleoporin gene NUP98. To ascertain the molecular features and the clinicopathological and prognostic significance of t(7;11)(p15;p15), 208 adult Chinese patients with AML were screened by Southern blot analysis with an HOXA9 cDNA probe and reverse transcription-polymerase chain reaction for NUP98/HOXA9. Three cases were found to have rearrangement of the HOXA9 gene. Two cases were found to have an NUP98/HOXA9 fusion transcript, with a breakpoint at NUP98 different from that previously described. The remaining case had no rearrangement of NUP98, nor was NUP98/HOXA9 detected. All positive cases had refractory AML with poor treatment outcome. In conclusion, t(7;11)/HOXA9 rearrangement was a rare event (3/208, 1.5%) in AML, even in a population where it was considered to be more prevalent. Two breakpoints in NUP98 may occur, and this is of importance in the design of primers to amplify t(7;11).