“…Molecular genetic studies have demonstrated that both inactivation of tumor-suppressor genes as well as oncogene amplification are important in the malignant progression of human gliomas (Holland, 2001). In particular, critical genes coding for growth factors, and their receptors (Ekstrand et al, 1991;Takahashi et al, 1992;Wong et al, 1992;Guha et al, 1995), as well as genes involved in cell cycle regulation (El-Azouzi et al, 1989;Jen et al, 1994;Henson et al, 1994;Reifenberger et al, 1994) are differentially overexpressed or altered in glial tumors. The progression to glioblastoma multiforme (GBM) involves losses of expression of tumor-suppressor proteins on chromosome 10 in a subset of tumors (Mollenhauer et al, 1997;Sano et al, 1999).…”