Glioblastoma Multiforme (GBM) is an aggressive neoplasm with an elevated, often aberrant, proliferative capacity and a diffuse pattern of brain invasion. It is the most malignant astrocytic tumor composed of poorly differentiated neoplastic astrocytes. GBM, also known as WHO grade-IV astrocytoma, is divided into two subtypes based on clinical characteristics: primary and secondary GBM. Primary GBM arises as a de novo process in the absence of a pre-existing low grade lesion, whereas secondary GBM develops progressively from a low grade astrocytoma, generally over a period of 5-10 years. Although most neurological tumors are of glial origin, it is unclear whether tumor cells result from the transformation of an immature precursor or from the de-differentiation of a mature glial cell...