Secondary near-pentaploidy and/or near-tetraploidy characterized by the duplication of 8;21 translocation in the M2 subtype of acute myeloid leukemia

Hyperploidy, especially near-tetraploidy, is rare in acute myeloid leukemia (AML). We report 2 cases with secondary hyperploidy characterized by doubl e 8;21 translocations. Morphologic observation of bone marrow smears reveal ed numerous giant blasts in both cases. Chromosome analyses with R-banding technique showed a karyotype of 46,XX,t(8;21)(2%)/92,XXXX, add(7)(q31)x2,t( 8;21) x2(7%)/100-117,XXX,-X,-X,-1,+4,+4,-7,+add(7)(q31)x3,t(8;21)x2+der(21) t(8;21),+22(90.6%)/ 46,XX(0.3%) in case 1 and a karyotype of 45,X,-Y,t(X;21 )(15%)/90,XX,-Y,Y,t(8;21)x2(80%)/46,XY(5%) in case 2. DNA ploidy analyses b y flow cytometry showed triple peaks (diploid, tetraploid [DI2.09] and near -pentaploid [DI2.59]) in case 1, and double peaks (diploid and near-tetrapl oid [DI2.07]) in case 2. Reverse-transcriptase polymerase chain reaction de tected an AML1/ETO fusion transcript (152bp) in both cases. This paper brin gs the total number of cases of secondary hyperploid t(8;21) AML to 6 and f urther emphasizes a correlation between hyperploidy and t(8;21) translocati on. Int J Hematol. 2000; 71:359-365. (C) 2000 The Japanese Society of Hemat ology.