Detection of multidrug resistance gene product (P-glycoprotein) expression in ependymomas.

A neurosurgical series of 33 ependymal tumours was examined for expression of the membrane transport molecule P-glycoprotein, which is linked with the development of multidrug resistance in many human tumours. We employed the monoclonal antibodies JSB1 and C219, raised to two different epitopes of the P-glycoprotein molecule, and found P-glycoprotein expression both in normal ependyma and in 29 of the tumours. This is the first time that ependymal tumours have been demonstrated to express the protein, and we conclude that its expression may contribute to the reported failure of adjuvant chemotherapy to improve outcome in ependymomas.