Expression of Isocitrate Dehydrogenase-1 (IDH-1) Mutant Protein in Gliomas

Abstract

Tumors of central nervous system (CNS) are uncommon neoplasms and comprise 1-2% of all the malignancies [1]. gliomas, the most common tumor of the CNS arise from the glia, the supporting cells of the central nervous system. Astrocytes, oligodendrocytes, and ependymal cells are types of glial cells that may give rise to astrocytoma, oligodendrogliomas, and ependymoma respectively. According to World Health Organization (WHO) 2007, these tumors are graded into four grades according to specific histopathological criteria and their biological behaviour rangingfrom grades I to IV. Glial neoplasmss develop as a result of genetic alterations that continuously accumulate with tumor progression. Molecular signatures of these tumors play roles as diagnostic, prognostic, and predictive markers and influence the clinical decision making process. Various genetic alterations described in the literature include 1p/19q co-deletion, O6-methylguanineDNA methyltransferase (MGMT) promoter hypermethylation and epidermal growth factor receptor (EGFR) alterations. The recent discovery of mutations of the isocitrate dehydrogenase-1 (IDH-1) gene in gliomas, in particular WHO grade II astrocytic, oligodendroglial, oligoastrocytic gliomass, and WHO grade III astrocytic tumors, is pointing toward a potentially common initiating event within this diverse group of tumors. Gliomass harbouring this mutation have been found to be associated with favourable prognosis [2,3].