Epidermal growth factor receptors on ependymomas and other brain tumors.

Epidermal growth factor receptor (EGFR) and transferrin receptor levels were determined in 14 intracranial neoplasms (four glioblastomas multiforme, four medulloblastomas, four ependymomas, one cerebellar astrocytoma, and one acoustic neurinoma) and in four samples of "normal" brain tissue. A competitive radioreceptor assay with 125I-epidermal growth factor and 125I-transferrin was performed using the primitive neuroectodermal tumor-derived TE-671 tissue-culture cell line as a standard. Epidermal growth factor receptors were present on TE-671 cells, all four ependymomas, and two of the four glioblastomas multiforme. The number of EGFR's per cell for ependymomas were estimated to range from 1000 to 6000. Transferrin receptors were detected on TE-671 cells, two of the four medulloblastomas, and one of the four glioblastomas multiforme. A cell surface binding assay, performed directly on the rat ependymal cell monolayer, was also analyzed. The identification of EGFR's on ependymomas and TR's on medulloblastomas suggests that malignant central nervous system tumors that spread by cerebrospinal fluid pathways may be treatable by intrathecal antibody-toxin conjugates. The presence of EGFR's on all of the ependymomas may reflect a role of the receptor in the malignant phenotype of this tumor.