DISTRIBUTION OF EPIDERMAL GROWTH-FACTOR RECEPTOR GENE AMPLIFICATION IN BRAIN-TUMORS AND CORRELATION TO PROGNOSIS

In 75 gliomas and 31 meningiomas, mutations at the epidermal growth fa ctor receptor (EGFR) gene locus were restricted to gliomas. The ligand s of this receptor, epidermal growth factor and transforming growth fa ctor alpha, lacked quantitative changes at their loci in gliomas and m eningiomas. EGFR gene amplification occurred in astrocytomas, oligoden drogliomas, ependymomas and glioblastomas. The frequency of this mutat ion significantly increased with the malignancy grade and the patient' s age. Especially in glioblastomas of individuals aged over 64 years, EGFR gene mutations were observed without Chromosome-10-specific allel e losses. This finding contradicts the hypothesis that deletion of one entire chromosome 10 regularly precedes EGFR gene amplification in pr imary glioblastomas of patients aged over 50 years. It was found that most individuals whose gliomas carry an EGFR gene mutation have a poor prognosis, comparable to that of glioblastoma patients even when the tumour is graded as benign.