Expression of Epidermal Growth Factor Receptor in Astrocytoma

ABSTRACT

It has been demonstrated that the epidermal growth factor receptor(EGFR) gene, the normal human counterpart of the viral erb-B oncogene, is amplified and overexpressed in 40-50% of malignant astrocytomas. Although little is known about the functional status of the overexpressed protein molecule, overexpression of a growth factor receptor evenly distributed throughout a tumor would be an ideal target for monoclonal antibody or growth factor receptor targeted therapy. We undertook the immunohistochemical study of the EGFR with malignancy grade. The results were as follows 1) Expression of EGFR was deteced in 1 case(6.7%) of low grade astrocytoma, 14 cases(63.6%) of anaplastic astrocytoma and 19 cases(73.1%) of glioblastoma multiforme. It was more frequent in malignant astrocytoma that low grade astrocytoma(p<0.01). 2) The distributed proportion and staing density of EGFR-expressed tumor cells was more increased in glioblastoma multiforme than anaplastic astrocytoma. 3) Regional heterogeneity of EGFR-expressed tumor cells was recognized in cases of EGFR expressed malignant astrocytoma. These results suggest that overexpression of EGFR would be involved in malignant progression of astrocytoma, and the use of monoclonal antibody or growth factor receptor targeted therapy maybe limited due to heterogeneity of EGFR expressed tumor cells in malignant asrotcytoma.