A novel translocation t(3;22)(q21;q11) involving 3q21 in myelodysplastic syndrome-derived overt leukemia with thrombocytosis

We report here a novel translocation t(3;22)(q21;q11) in myelodysplastic sy ndrome (MDS)-derived overt leukemia with thrombocytosis. A 44-year-old fema le was initially diagnosed as MDS with a low platelet count and normal kary otype. After 4 months, blood leukemic cells and platelets rapidly increased concomitantly and a diagnosis of acute myeloblastic leukemia (AML M1) was made. Chromosome analysis showed 46, XX, t(3;22)(q21;q11) in 14 of 20 metap hases. Fluorescence in situ hybridization analysis confirmed both the der(3 )t(3;22) and the der(22)t(3;22). Our results suggest that unidentified gene (s) at 3q21 breakpoint may be implicated in the pathogenesis of abnormal th rombopoiesis as observed in the 3q21q26 syndrome. (C) 2000 Elsevier Science Ltd. All rights reserved.