Measurement of multidrug resistance in acute leukemia with three methods (Pgp expression, dnr accumulation & rho accumulation).

12001 Background: Multidrug resistance (MDR) is one of the most important causes of treatment failure in chemotherapy specially in acute leukemias. One of the MDR resistance mechanisms is mdr1 gene expression that causes P-glycoprotein (Pgp) expression on cell surface. Its expression and function is detected by flowcytometry. we decided to measure its expression by three method in our leukemias patients. Then we studied correlation of each of these tests with relapse, resistance, survival and some other parameters.,before chemotherapy bone marrow. Pgp expression was detected with MRK16 Ab. For interpreting of Pgp we use D-value. D-value >0.15 was considered positive for Pgp. For dnr accumulation & rho accumulation D-value >0.2 was considered positive. Informations was colleced from patient chart. Correlation of OS, DFS, resistance to therapy with Pgp expression by each method was studied.,there were 84 patients (52 male & 32 female). 18 cases of ALL & 66 cases of AML were included. Mean age was 30 ± 13 and mean of follow up was 168 ± 106 days. Mean of dPgp was 0.35 ± 0.05, mean of ddnr was 0. 5 ± 0.28 and mean of drho was 0. 5 ± 0.28 too. There was significant correlation between patients presented with first relapse and dPgp (p-value < 0.009).But there was not true for ddnr or drho.Sensitivity and specifity of Pgp for resistance to therapy was 35% & 75% respectively. Sensitivity and specifity of dnr accumulation for resistance to therapy was 11% & 76% respectively. Sensitivity and specifity of Pgp for resistance to therapy was 11% & 76% respectively. There is on significant correlation between Pgp and OS. It was true for dnr accumulation & rho accumulation. RFS was longer for patients with negative Pgp, but there was not significant correlation. In patients with positive Pgp probability of relapse was 9 times more than negative Pgp.,among these three tests Pgp expression is more useful for predicting resistance to therapy. There is no difference between dnr accumulation and rho accumulation in detecting resistance to therapy. But sensitivity of Pgp expression in detecting resistance to therapy is more than the two other tests. We can use Pgp expression as a helpful test for recognizing more resistant disease. No significant financial relationships to disclose.