MDR1 GENE-EXPRESSION IN CHRONIC LYMPHOCYTIC-LEUKEMIA

In order to assess the clinical role of the MDR1 gene in chronic lymph ocytic leukemia (CLL), we determined its expression in the leukemic ce lls of 39 patients with CLL and compared this with other clinical and laboratory parameters. MDR1 RNA expression was detected in 29 patients . MDR1 RNA transcripts were independent of age, treatment status of th e patients and the clinical stage of CLL, but correlated with the whit e blood cell count and MDR2 RNA transcripts. Expression of the tumor s uppressor gene p53 was found in 30 out of 37 patients and was associat ed with MDR1 RNA expression (P < 0.001). Immunocytochemistry using the monoclonal antibody C219 was performed in 38 patients, and in 28 case s, more than 5% of the leukemic cells were found to express cell surfa ce P-glycoprotein. P-glycoprotein expression correlated with the expre ssion of MDR1 RNA (P = 0.048).