assessment of p-glycoprotein

drug resistance is one of the most significant challenges facing clinicians who treat malignancies. Despite major advances in cancer chemotherapy, many patients develop recurrent disease after initially responding well to therapies.A representative cause of MDR is the expression of MDR 1 gene and its product, P-glycoprotein, on the cell surface membrane.Pgp is the best-characterised drug resistance molecule in AML. Consequently, various attempts have been made to circumvent the adverse outcome associated with pgp expression by using drug efflux modulators such as cyclosporine A.The main aim of the study was to evaluate Pgp overexpression in patients with refractory or relapsed acute myeloid leukemia and response to cyclosporine A in addition to chemotherapy.In order to achieve this aim, we selected forty patients with refractory or relapsed acute myeloid leukemia. they were 18 males (45%) and 22 females (55%) selected from hematology and medical oncology unit , internal medicine department , Zagazig university hospital.Patients were classified into two groups:-Group (A): included 20 adult patients, they were treated with chemotherapy alone (Ara-C 1 gm/ m2/12 hour 3 hour I.V. infusion from day 1-3 + Novantron 10 mg/ m2 I.V. infusion from day 3-5).Group (B): included 20 adult patients, they were treated with oral Cyclosporine A (5 mg/kg/d for 5 successive days) in addition to the chemotherapy given in the same protocol as in group A.All patients were subjected to complete clinical History and physical Examination, routine laboratory investigations, radiological studies and Special laboratory investigation to assess PgP overexpression.