title: Molecular variants of epidermal growth factor in malignant astrocytoma.
abstract: The present study has measured EGF levels in primary brain tumor tissues. EGF levels were measured by specific radioimmunoassay (RIA) and further analyzed by reversed-phase high performance liquid chromatography (RP-HPLC) followed by RIA and radioreceptor binding. The levels of EGF-like immunoreactivity (EGF-LI) in astrocytoma-IV tumors were fourfold greater than those in normal brain tissues. In astrocytoma-II and astrocytoma-III tumors, however, levels of EGF-LI were not different from those in normal brain. HPLC analysis of extracts from normal brain tissue and astrocytoma-II showed one peak of EGF-LI that coeluted with standard human EGF (retention time 22 min). Interestingly, EGF-LI in extracts of astrocytoma-IV tumors eluted in two distinct peaks with retention times of 24 and 26 min (Astro-A and Astro-B, respectively). Materials in both Astro-A and Astro-B peaks reduced the specific binding of [125I]hEGF to EGF receptors in human placental membranes. These studies demonstrate elevated levels of EGF-LI in malignant astrocytoma, but not in benign tumors. Furthermore, two different EGF-like molecules that are different from native EGF are present in malignant astrocytoma.
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston 29403, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Rao
authors.forename: M
authors.initials: M
authors.lastname: Shantaram
authors.forename: A R
authors.initials: AR
authors.lastname: Aroor
authors.forename: A
authors.initials: A
authors.lastname: Raja
authors.forename: T P
authors.initials: TP
authors.lastname: Davis
authors.forename: A
authors.initials: A
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D001254:Astrocytoma / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000378:metabolism*; D002648:Child; D002851:Chromatography, High Pressure Liquid; D004815:Epidermal Growth Factor / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011863:Radioimmunoassay; D011869:Radioligand Assay
chemical_list: D004815:Epidermal Growth Factor