2010 Volume 19 Issue 1 Pages 12-18
The current practice of relying solely on microscopic examinations for histological classification of gliomas and, consequentially, determination of optimal treatment, appears to be insufficient. As a result of the increasing use of molecular markers in tumor classification, there is an emerging emphasis in the genetic profiles of distinct subtypes of glioma. These subtypes of glioma constitute distinct disease entities that evolve through different genetic pathways, and are likely to differ in prognosis and response to therapy. Status of O6-methylguaninemethyltransferase（O6-MGMT） gene is associated with the resistance to temozolomide（TMZ）. We have previously found methylation or expression mosaicism of O6-MGMT in gliomas, resulting in problems on tumor sampling and respose to TMZ. An assessment of O6-MGMT methylation mosaicism in heterogeneous glioma may provide a more accurate assessment for the response to TMZ. Oligodendroglioma is recognized as a particular subtype of gliomas that shows remarkable response to chemotherapy（procarbazine + CCNU + vincristine（PCV）, making their correct diagnosis important. Loss of heterozygosity（LOH） on chromosomes 1p and 19q is correlated with sensitivity to PCV chemotherapy with increased survival in anaplastic oligodendroglioma cases（WHO grade III）. This article reviews biological and molecular approaches to glioma classification that have the potential to increase the efficacy of treatments for these tumors.
