P-GLYCOPROTEIN EXPRESSION IN CHRONIC LYMPHOCYTIC-LEUKEMIA - ASSOCIATION WITH CHEMOTHERAPY

P-glycoprotein (PgP), a transmembrane protein, has been associated wit h multiple drug resistance. We examined 42 patients with chronic lymph ocytic leukemia immunohistochemically using the monoclonal antibody JS B-1 to determine the prevalence of PgP expression and its relationship with chemotherapy exposure. Of the 42 patients, 31 (74%) had detectab le PgP. No relationship was found between PgP expression, patient age, duration of disease or stage. Moderate and strong intensity staining was found in 22% of untreated patients versus 56% patients treated wit h chemotherapy (p<0.05). Temporal fluctuations in P-glycoprotein stain ing intensity was seen in 6 of 7 cases which paralleled the initiation or withdrawal of the therapy.