Expression of the novel NUP98/PSIP1 fusion transcripts in myelodysplastic syndrome with t(9;11)(p22;p15)

Objectives:  The t(9;11)(p22;p15) is a very rare but recurrent translocation in acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) blast crisis. The translocation results in a fusion gene between NUP98 at 11p15 and PSIP1 encoding two transcriptional coactivators, p52 and p75, at 9p22. Here, we describe the first case of myelodysplastic syndrome (MDS) with t(9;11)(p22;p15). Patient:  A 64‐yr‐old woman presented pancytopenia, trilineage dysplasia, and 9.2% blasts in the bone marrow, indicating the diagnosis of MDS. Results:  G‐banding and spectral karyotyping showed 46,XX,t(9;11)(p22;p15)[20]. Reverse transcription‐polymerase chain reaction (RT‐PCR) and nucleotide sequencing detected four types of NUP98/PSIP1‐p52 and two types of NUP98/PSIP1‐p75 fusion transcripts. Essentially, the NUP98 exon 12 or exon 11 by alternative splicing was fused in‐frame with the PSIP1 exon 8. Real‐time quantitative (RQ) PCR for NUP98/PSIP1/GAPDH demonstrated a 4‐log decrease after cord blood transplantation and a 2‐log increase at relapse. Conclusions:  The fusion genes combining NUP98 exon 11/12 with PSIP1 exon 8, which have never been detected in other AML/CML cases, may be implicated in the pathogenesis of MDS. Furthermore, RQ‐PCR for NUP98/PSIP1 could be useful to monitor minimal residual disease.