Multidrug resistance gene transcript level, and P-glycoprotein expression in paediatric malignant mesenchymal tumours.

Twenty-four malignant mesenchymal tumour specimens were analysed for human multidrug resistance (MDRI) gene transcript levels using Northern and slot blot techniques. The presence of P-glycoprotein was assessed in 12 of the 24 samples by immunohistochemistry using the monoclonal antibody (MAb) C219. Increased MDRI transcript levels were found in 2 (8.3%), while, using immunohistochemistry, 2 samples were positive and 3 faintly positive (41.6%). Overall, elevated P-glycoprotein or MDRI transcript levels were found in tumours of 6 patients, 3 of whom are dead. The relationship to MDRI expression and subsequent resistance to chemotherapy has to be established.