Oligodendrogliomas lacking O6-methylguanine-DNA-methyltransferase expression.

Abstract

O6-Methylguanine-DNA-Methyltransferase (MGMT) is a DNA repair protein considered to be a chemosensitivity predictor. We evaluated the immunohistochemical MGMT expression in 28 consecutive oligodendroglial tumors (21 oligodendrogliomas, 5 mixed oligoastrocytomas, and 2 glioblastomas with prominent oligodendroglial features; 13 treated with CCNU) and compared it with that of 13 glioblastomas. Twenty-six (93%) oligodendroglial tumors were MGMT-negative, 2 (7%) were MGMT-positive. Twelve (92%) patients treated with CCNU had MGMT-negative lesions and their median survival was 73 months; 1 patient had an MGMT-positive oligodendroglioma and is alive at 28 months. Three (23%) glioblastomas were MGMT-negative and 10 (77%) MGMT-positive. The lower MGMT expression in oligodendroglial tumors compared to glioblastomas (P < 0.05), which have different chemosensitivity, suggests a possible role of MGMT in the determination of chemoresistance. Nevertheless, the heterogeneous outcome of our MGMT-negative oligodendroglial tumors treated with CCNU, indicates that MGMT expression alone is insufficient to predict the response to alkylating drugs, presumably because of the numerous mechanisms involved.

• Authors: A M Buccoliero, L Arganini, F Ammannati, P Gallina, N Di Lorenzo, P Mennonna, G L Taddei
• Journal: Journal of chemotherapy (Florence, Italy) (J Chemother) Vol. 17 Issue 3 Pg. 321-6 (Jun 2005) ISSN: 1120-009X [Print] England
• PMID: 16038527 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Antineoplastic Agents
• Nitrosourea Compounds
• O(6)-Methylguanine-DNA Methyltransferase

Topics

• Adult
• Aged
• Antineoplastic Agents (pharmacology)
• Brain Neoplasms (genetics, pathology)
• DNA Repair
• Drug Resistance, Neoplasm
• Female
• Gene Expression Profiling
• Glioblastoma (genetics, pathology)
• Humans
• Immunohistochemistry
• Male
• Middle Aged
• Nitrosourea Compounds (pharmacology)
• O(6)-Methylguanine-DNA Methyltransferase (analysis, genetics)
• Oligodendroglioma (genetics, pathology)
• Survival Analysis