Clinical impact of molecular biomarkers in gliomas.

The World Health Organization (WHO) classification system for glial tumors provides guidance as to the predicted course of the disease and choice of treatment. However, histologically identical tumors may have a very different outcome and response to treatment. Molecular markers that carry both diagnostic and prognostic information add valuable tools by redefining tumor subtypes within each WHO category. Therefore, molecular biomarkers have become an integral part of tumor assessment in modern neuro-oncology and biomarker status now guides clinical decisions in some subtypes of gliomas, including anaplastic oligodendroglioma and glioblastoma in the elderly. This review discusses the prognostic and predictive impact of molecular markers that have undergone extensive study in recent years. The clinical relevance of contemporary molecular classification of gliomas using the routine assessment of IDH mutations, promoter methylation of MGMT, chromosomal deletion of 1p/19q, mutations of EGFR and ATRX genes, and BRAF fusion or point mutation is highlighted. The potential of molecular biomarker-based classification to guide future therapeutic approach is discussed and accentuated.