Treatment offered at present to the vast majority of patients with myelodysplastic syndromes (MDS), mostly refractory anemia (RA) and refractory anemia with ringed sideroblasts, is retricted to supportive care only. This report delineates an unusual experience with Hydroxyurea (HU) given to a patient with RA subtype of MDS with myeloproliferative feature (thrombocytosis) and abnormal chromosome. A significant improvement of anemia along with a decrease in the platelet count and a parallel decrease in the number of the cells with abnormal karyotype followed invariably after a short-term HU therapy. Cytotoxic effects to abnormal hematopoietic cell clone, suppressive effect to c-myc which enhances apoptosis, decrement of the cells susceptible to pathogenetic cytokine effects, and erythroid differentiation activity were considered pertinent mechanisms of action of HU.
Keywords: Hydroxyurea; Myelodysplastic syndromes; chromosome studies; mechanisms of action; myeloproliferative features.