OBJECTIVETo study the biological characteristics and treatment response of patients with myelodysplastic syndrome (MDS) transformed into acute leukemia(AL).

METHODSUsing WHO standard method, the clinical characteristics of patients with MDS into AML were retrospectively analyzed, the related factors influencing the MDS into AML and the treatment response of patients were analyzed.

RESULTSTwenty-six cases (17%) of MDS were transformed into AL among 153 cases of middle and high risk MDS, all of which were AML. The median time of transformation from MDS into AML was 4 months (1-29),and these cases transformed into AML-M2, M4, M5 and M6. In these 26 cases of AML patients, the varying degrees of anemia symptom appeared, 2 cases were with marrow infiltration, 18 cases (69.2%) were with abnormal chromosome karyotype. Compared with karyotype before transformation into AML, the abnormal karyotype in 9 cases had been conversed (new karyotype or disappear once of existing karyotype). Total efficiency of individualized treatment for MDS transformed into AML was 80%. This treatment could improve the patients quality of life.

CONCLUSIONMiddle and high risk MDS patients are prone to be tranformed into AML. Multiple factors are involved in the transformation of MDS into AML. These patients showed the special biological characteristics and poorer prognosis. Demethylation treatment is helpful to achieve a good near-term curative effect.