This review focuses on genes that have a proven or presumed role in the genesis of astrocytic tumors. A common theme in glioblastoma is the amplification of genes that code for growth factor receptors of the protein-tyrosine kinase family (epidermal growth factor receptor, platelet-derived growth factor receptor-alpha, met). The majority of glioblastomas also have alterations in genes that encode factors that are involved in cyclin-dependent kinase activity, which is a critical step in G1-S transition in the cell cycle. These alterations include deletions of negative regulatory elements (TP53, CDKN2, MTS2) and amplification of positive factors (MDM2, CDK4). In addition, there are loci on chromosomes 10 and 19q that seem to be involved in tumor progression.