Acute leukemic transformation of myelodusplastic syndrome-immunopic, genotypic, and cytogenetic studies

　　The clinical and biogical characteristics of myelodysplastic syndrome (MDS) in acute leukemic transformation were studied in 23 patients. All had myeloid transformation according to FAB criteria, but coexpression of lymphoid-associated antigens was detected in five of the 20 patients who underwent and immunophenophenotypic study. Rearrangement of the immunoglobulin heavy chain gene was also observed in one of the five patients　who coexpressed lymphoid markers and that of the T-cell receptor chain gene in another one. None had pure lymphoid transformation. Clonal chromosomal abnormalities were noted in 12 (63%) of the 19 patients who underwent cytogenetic study, most commonly -7 (six patients or additional aberrations were +8 and +21. N-ras gene mutation was detected in two of the nine patients at acute leukemic transformation was 10months (1-36 months). Patients with a normal karyotype at diagnosis had a significantly longer chronic phase duration than those with chromosomal abnormalities(median of 20 months vs. 5 months). However, all had a short survival time after diagnosis of acute leukemia, whether chromosomal anomalies were present or not.#1666#