Leweke F, Damian M S, Schindler C, Schachenmayr W
Neurologic Clinic, Justus Liebig University, Giessen, Germany.
Pathol Res Pract. 1998;194(3):149-55. doi: 10.1016/S0344-0338(98)80015-0.
Chemosensitivity of previously untreated glioblastomas to mitoxantrone, methotrexate, ACNU and BCNU was tested on cultured tissue. Sixteen of 62 tumors were partially chemosensitive in vitro. The monoclonal antibody C 219 was used to demonstrate the presence of p-glycoprotein in the 16 sensitive and five highly resistant glioblastomas. All 21 tumors identically expressed p-glycoprotein. These results show that untreated glioblastomas primarily express p-glycoprotein even if they are at least partially chemosensitive in vitro. Therefore, immunohistochemical demonstration of p-glycoprotein with the monoclonal antibody C 219 can not provide reliable information on short term resistance of the individual tumors to antineoplastic drugs. P-glycoprotein expression could, however, help to explain the disappointing overall long-term efficacy of chemotherapy by showing the existence of cell populations with early drug resistance in these tumors.
