High-level Expression of P-glycoprotein and 85 kD Protein as Assessed by Flow Cytometry and Immunocytochemistry in Leukemias and Malignant Lymphomas UMEDA Yoshikatsu TSURUO Takashi MORI Shigeo ARIMORI Shigeru SUGAWARA Isamu 東海大学 Tokai journal of experimental and clinical medicine 03850005 15 2 179 187 1990-03-08 Acquired resistance developed after chemotherapy is characterized by lower sensitivity to anticancer agents. We utilized two monoclonal antibodies (MABs): MRK16 which recognized 170 to 180 kD P-glycoprotein and MRK20 which recognized 85 kD protein, to investigate the frequency of multidrugresistant cancer cells appearing during treatment of 23 cases of leukemias and 27 cases of malignant lymphomas. The reactivities of these MABs with lymphocytes and blastic cells were examined by flow cytometry and immunocytochemistry. The following findings were obtained. First, among 50 cases, increaes in MRK16-reactive cells and MRK20-reactive cells were noted in 17 cases (34%) and 28 cases (56%), respectively. Second, the increase of MRK16-positive cells in three cases and the increase of MRK20-positive cells in two cases were correlated with dosages of the corresponding anticancer drugs used. Although we investigated the total amounts of anti-cancer drugs used, we were not able to detect exactly when P-glycoprotein recognized by MRK16 and the 85 kDa protein recognized by MRK20 appeared in these resistant cells during treatment. More cases will be required to investigate the significance between treatment and reactivity of MRK16 or MRK20 with leukemia or lymphomas cells. 1990-03-08 110004701196 AA00863975 ENG NII-ELS 3 High-level Expression of P-glycoprotein and 85 kD Protein as Assessed by Flow Cytometry and Immunocytochemistry in Leukemias and Malignant Lymphomas UMEDA Yoshikatsu TSURUO Takashi MORI Shigeo ARIMORI Shigeru SUGAWARA Isamu Tokai University Tokai journal of experimental and clinical medicine Acquired resistance developed after chemotherapy is characterized by lower sensitivity to anticancer agents. We utilized two monoclonal antibodies (MABs): MRK16 which recognized 170 to 180 kD P-glycoprotein and MRK20 which recognized 85 kD protein, to investigate the frequency of multidrugresistant cancer cells appearing during treatment of 23 cases of leukemias and 27 cases of malignant lymphomas. The reactivities of these MABs with lymphocytes and blastic cells were examined by flow cytometry and immunocytochemistry. The following findings were obtained. First, among 50 cases, increaes in MRK16-reactive cells and MRK20-reactive cells were noted in 17 cases (34%) and 28 cases (56%), respectively. Second, the increase of MRK16-positive cells in three cases and the increase of MRK20-positive cells in two cases were correlated with dosages of the corresponding anticancer drugs used. Although we investigated the total amounts of anti-cancer drugs used, we were not able to detect exactly when P-glycoprotein recognized by MRK16 and the 85 kDa protein recognized by MRK20 appeared in these resistant cells during treatment. More cases will be required to investigate the significance between treatment and reactivity of MRK16 or MRK20 with leukemia or lymphomas cells. UMEDA Yoshikatsu Department of Internal Medicine, School of Medicine, Tokai University TSURUO Takashi Cancer Chemotherapy Center, Japanese Foundation for Cancer Research MORI Shigeo Department of Pathology, The Institute of Medical Science, The University of Tokyo ARIMORI Shigeru Department of Internal Medicine, School of Medicine, Tokai University SUGAWARA Isamu Department of Pathology, Saitama Medical Center, Saitama Medical School