Biopsy specimens of 19 human gliomas (10 glioblastomas, 2 anaplastic astrocytomas, 4 astrocytomas, one mixed glioma, one oligodendroglioma and one ependymoma) were examined for amplification of tumour-related genes located on chromosome 7: the proto-oncogene c-erb-B1 (encoding the epidermal growth factor receptor (EGFR], the proto-oncogene c-met, the platelet-derived growth factor A-chain gene, and the plasminogen activator inhibitor type-1 gene. Gene amplification was observed in 6 glioblastomas, and the EGFR gene was the only chromosome-7-gene examined that was amplified. The selective EGFR gene amplification in human glioblastomas suggests its potential role in the progression of some of these tumours.