Additional acquisition of t(1;21)(p32;q22) in a patient relapsing with acute myelogenous leukemia with NUP98-HOXA9

We report a 29-year-old Japanese male with acute myelogenous leukemia (AML)-M4 with a cryptic t(7;11)(p15;p15), in which a chimeric NUP98-HOXA9 fusion was detected by polymerase chain reaction analysis and a chromosomal analysis showed 46,XY. The patient received intensive chemotherapy and underwent autologous stem cell transplantation, and remission was confirmed by the disappearance of NUP98-HOXA9. However, 6 months after transplantation, the patient relapsed; NUP98-HOXA9 was detected again and karyotypic analysis revealed 46,XY, t(1;21)(p32;q22). Fluorescent in situ hybridization (FISH) analysis using an AML1-ETO translocation dual probe, showed that the 21q22 breakpoint involved AML1 locus. A retrospective FISH analysis showed that t(1;21) was absent at onset. This is the first reported case with AML who had a cryptic t(7;11)(p15;p15), and additionally acquired t(1;21)(p32;q22) at relapse.