Monosomal karyotype in MDS: explaining the poor prognosis?

Monosomal karyotype (MK) is associated with an adverse prognosis in patients in acute myeloid leukemia (AML). This studyanalyzes the prognostic impact of MK in a cohort of primary, untreated patients with myelodysplastic syndromes (MDS). A total of431 patients were extracted from an international database. To analyze whether MK is an independent prognostic marker in MDS,cytogenetic and clinical data were explored in uni- and multivariate models regarding overall survival (OS) as well as AML-freesurvival. In all, 204/431 (47.3%) patients with MK were identified. Regarding OS, MK was prognostically significant in patients withp4 abnormalities only. In highly complex karyotypes (X5 abnormalities), MK did not separate prognostic subgroups (median OS4.9 months in MKþ vs 5.6 months in patients without MK, P¼0.832). Based on the number of abnormalities, MK-positivekaryotypes (MKþ) split into different prognostic subgroups (MKþ and 2 abnormalities: OS 13.4 months, MKþ and 3abnormalities: 8.0 months, MKþ and 4 abnormalities: 7.9 months and MKþ and X5 abnormalities: 4.9 months; Po0.01). Inmultivariate analyses, MK was not an independent prognostic factor. Our data support the hypothesis that a high number ofcomplex abnormalities, associated with an instable clone, define the subgroup with the worst prognosis in MDS, independentof MK.Leukemia (2013) 27, 1988–1995; doi:10.1038/leu.2013.187Keywords: MDS; monosomal karyotype; cytogenetics; prognosisINTRODUCTIONMyelodysplastic syndromes (MDS) are clonal disorders of thehematopoietic stem cell, associated with peripheral cytopeniasand the risk of transformation into acute myeloid leukemia(AML).