Cytogenetic profile of myelodysplastic syndromes with complex karyotypes: an analysis using spectral karyotyping.

We have performed a cytogenetic analysis of 23 myelodysplastic syndromes (MDS) with complex karyotypes (CK) using GTG-banding and spectral karyotyping techniques. Fifty-five percent of cases were hypodiploid, 34% were hyperdiploid, and 11% were pseudodiploid. The most recurrent alterations were monosomy of chromosomes 18, 5, and 7; trisomy of chromosome 8; and deletion of 5q, 11q, and 12p. Ninety-two structural alterations were mostly identified as unbalanced. The chromosomes and regions more frequently affected were 16q12, 17p11, and 20q11. Eight of 92 structural alterations were reciprocal translocations. Two translocations were recurrent, t(X;20)(p11.4;q11.2) and der(17)t(5;17)(?;p11.2); each one was present in about 10% of cases (2 cases, t[X:20] and 3 cases, t[5:17]). Mutations of TP53 were observed in five cases (22%), all with rearrangements affecting 17p. Total or partial inactivation of TP53 was detected in six cases (26%) as a result of loss of either both copies (four cases) or just one copy (two cases). Fluorescence in situ hybridization analysis showed amplification of genes previously identified in myeloid and/or hematological processes, such as HER2neu, MLL, and AML1, which could represent frequent events in MDS with CK.