Multidrug Resistance in Myelodysplastic Syndromes and Acute Leukemia

摘要: Myelodysplastic syndromes (MDS) comprise a heterogeneous group of acquired clonal bone marrow disorders with an increased risk transformation to acute myeloid leukemia (AML). In these disorders, aggressive chemotherapy usually yields results inferior those achieved in de novo AML [1]. The biological basis the reduced responsiveness preleukemic cell clone is unknown. However, evidence from cytogenetic and epidemiological studies suggests that it may be related potential differences tumor initiation and/or progression. Increased drug resistance expression multidrug (MDR) phenotype, designated as Pglycoprotein, have been observed hemopoietic cells patients MDS prior exposure cytotoxic therapy [2]. It has demonstrated frequence gene mutations increases progression [3]. Observations Kadoyama [4] implicating participation protooncogenes regulation MDR suggest acquisition proliferative signals promote P-glycoprotein such cases. mediates multiple, structurally dissimilar drugs including anthracyclines, actinomycin D, vinca alkaloids, epipodophyllotoxins. As substances represent integral components antileukemic regimens, we tried determine prognostic value advanced or undergoing chemotherapy.