Moreover, MDR-1C3435T may have a protective effect against MDS progression because the expected lower expression of P-glycoprotein would lead to a higher degree of cell death.
The MDR1 expression rate was significantly correlated with factors such as a history of preceding chemotherapy, elder age of the patient, and certain disease types (eg, leukemia progressed from myelodysplastic syndrome).
Quinine improves results of intensive chemotherapy (IC) in myelodysplastic syndromes (MDS) expressing P-glycoprotein (PGP). Updated results of a randomized study. Groupe Français des Myélodysplasies (GFM) and Groupe GOELAMS.
This P-gp(+) drug resistance could be due either to a particular phenotype of bad prognosis AML, as it is suggested by the association of myelodysplasia, complex karyotype and advanced age with MDR1 phenotype, or due primarily to the active efflux of anthracyclines and VP16 in P-gp(+) leukemic cells.
Analysis of the characteristics of folate binding proteins and its relationship with expression of multidrug resistance P-glycoprotein in myelodysplastic syndromes.
To evaluate the clinical relevance of multidrug resistance (MDR) phenotype, the intracellular daunorubicin accumulation (IDA) and P-glycoprotein (P-gp) expression were investigated in 87 adult patients with acute leukemia: 69 patients with de novo acute myeloid leukemia (AML), 10 with AML at relapse, and eight with secondary leukemia to myelodysplastic syndromes (MDS-AML).
Intrinsic characteristics of leukaemic cells, especially expression of the MDR1 gene, in vitro growth of the leukaemic clonogenic cells and sensitivity to daunorubicin-(+)cytosine arabinoside, did not differ according to age, except that there was a higher incidence of previous myelodysplastic syndromes and a lower incidence of good prognostic cytogenetics in the elderly patients.
It is concluded that MDR-1 expression in MDS is present in cells with an immature phenotype and is frequently observed in patients who have an abnormal karyotype and a high risk of leukemic transformation.