DETECTION OF MULTIDRUG-RESISTANCE GENE-PRODUCT (P-GLYCOPROTEIN) EXPRESSION IN EPENDYMOMAS

A neurosurgical series of 33 ependymal tumours was examined for expres sion of the membrane transport molecule P-glycoprotein, which is linke d with the development of multidrug resistance in many human tumours. We employed the monoclonal antibodies JSB1 and C219, raised to two dif ferent epitopes of the P-glycoprotein molecule, and found P-glycoprote in expression both in normal ependyma and in 29 of the tumours. This i s the first time that ependymal tumours have been demonstrated to expr ess the protein, and we conclude that its expression may contribute to the reported failure of adjuvant chemotherapy to improve outcome in e pendymomas.