CD133, a putative stem cell marker in normal tissue and malignant brain tumors, enhances multidrug resistant gene 1 (MDR1) expression following chemotherapy in adult malignant glioblastomas.
The data indicate that knowledge of the expression levels of MGMT and mdr1 may be particularly useful for a more rational selection of drugs which are not influenced by these resistance genes and which have improved efficacy against human brain tumors.
To examine whether brain tumors overexpress the MDR1 gene, 25 brain-tumor specimens were subjected to Northern blot analysis: 10 gliomas, eight meningiomas, three schwannomas, one malignant lymphoma, and three tumors metastatic to the brain.