[Factors influencing leukemic transformation in myelodysplastic syndrome]

Prognostic factors affecting the leukemic transformation were studied in 43 patients with myelodysplastic syndrome (MDS). Acute leukemia developed in 17 cases and it was nonlymphocytic leukemia in every case. No remission was achieved following antileukemic therapy and most of the cases proved to be true drug-resistant leukemia. Initial granulopenia, thrombopenia or anemia alone did not influence the occurrence of leukemic transformation but pancytopenia indicates bad prognosis. According to FAB classification especially refractory anemia with excess of blasts (RAEB) and RAEB in transformation (RAEB-T) were often followed by leukemic transformation. The granulocyte-macrophage progenitor cell (GM-CFC) content of bone marrow were also studied. The GM-CFC content was decreased in each patient. There was no correlation between GM-CFC number and leukemic transformation, the growth-pattern in agar-gel culture, however, turned out to have prognostic importance. Leukemic type of growth, namely always preceded leukemic transformation.