Cytogenetic studies of a series of 43 consecutive secondary myelodysplastic syndromes/acute myeloid leukemias: conventional cytogenetics, FISH, and multiplex FISH

We report a series of 43 consecutive therapy-related myelodysplastic syndromes (t-MDS) or acute myeloid leukemias (t-AML) observed for 6 years. This series consisted of 26 women and 17 men, ages ranging from 9 to 85 years. These cases were classified into three groups according to the primary diagnosis. Conventional cytogenetic and fluorescent in situ hybridization (FISH)/ multiplex FISH (M-FISH) methods were used to analyze cytogenetic characteristics of secondary MDS/AML. The features of chromosomal abnormalities were linked to the nature of the therapy and protocols used. A considerable proportion of recurrent balanced translocations characterized t-AML secondary to therapy. FISH techniques showed that conventional cytogenetics often underestimated associated translocations; some deletions were in fact derivative chromosomes associated with deletions. After treatment for lymphomas and chronic myeloproliferative diseases, there were more complex unbalanced abnormalities than the control group. Compared to other series, recurrent translocations appeared to be more numerous (25%), probably reflecting an evolution of therapeutic modalities.