Expression of MRP in lymphoma samples and cell lines was measured by PCR as described in the Materials and Methods section. (A) 16 biopsy samples obtained at diagnosis of lymphoma, 55 biopsy samples obtained from patients, 36 pre-EPOCH and 19 post-EPOCH, and three cell lines and their respective MRP-overexpressing sublines. (B) Serial samples obtained from 15 patients pre- and post-EPOCH. The four samples included without percent tumor determination are marked with an asterisk.