Novel NUP98-HOXC11 fusion gene resulted from a chromosomal break within exon 1 of HOXC11 in acute myeloid leukemia with t(11;12)(p15;q13).

The NUP98 gene has been reported to be fused to 11 partner genes in hematological malignancies with 11p15 translocations. Among NUP98 fusion partner genes, HOXA and HOXD clusters have been reported thus far; however, no HOXC or HOXB clusters have been reported. We identified a novel NUP98-HOXC11 fusion gene in a pediatric patient with de novo acute myeloid leukemia having t(11;12)(p15;q13). The breakpoint of NUP98 was located within a LINE repetitive sequence (HAL1) in intron 12, and the breakpoint of HOXC11 was located within exon 1, resulting in a NUP98-HOXC11 in-frame fusion transcript containing exon 12 of NUP98 fused to a part of exon 1 of HOXC11 with an 8-bp insertion derived from the intron sequence just 5' of the breakpoint of NUP98. The NUP98-HOXC11 fusion protein consists of the NH2-terminal phenylalanine-glycine repeat motif of NUP98 and the COOH-terminal homeodomain of HOXC11. Although the frequency of HOXC11 expression was not high in leukemia cell lines, its expression was significantly more frequent in myeloid than lymphoid leukemia cell lines. These data suggest that the NUP98-HOXC11 fusion protein plays a role in the pathogenesis of myeloid malignancies.