 The epidermal growth factor EGF is an important biological mediator of normal growth and repair and is critical to epithelial tissue development and maturation of the central nervous system, among other functions. EGF is a natural focus of interest in cancer research because of its influence over mitogenesis, proliferation, and tumorigenesis. In addition, unregulated expression of its receptor, EGFR, has been identified as a common event in neoplastic transformation. In patients with the most malignant primary tumor of the brain, the glioblastoma multiforme GBM, alterations in the EGFR or in its expression levels have been identified in approximately 50 of patients. We postulate that EGF-EGFR interactions may be important for the development, progression, and prognosis of human gliomas and that alterations of the EGF gene may predict the potential for glioma progression and the severity of disease. 