title: Evaluation of ENU-induced gliomas in rats: nomenclature, immunochemistry, and malignancy.
abstract: Rats developed mixed gliomas, oligodendrogliomas, and a few astrocytomas in response to transplacental ethylnitrosourea. The neoplastic cell composition of mixed gliomas must be defined; this study required a 20-80% admixture of neoplastic astrocytes and oligodendroglia for the diagnosis of mixed glioma. A battery of immunoantibodies, including Leu-7, S-100, and vimentin, were helpful in classifying rat gliomas, and the histologic features of each tumor type are described. Other brain tumor characteristics that may decide the outcome of carcinogenicity studies include incidence, multiplicity, latency, fatality, size, and malignancy. The size of tumors was determined by measuring their 3-dimensional volumes. Brain tumor volume was found to be highly correlated with malignancy and fatality. Systematic evaluation of the malignancy of brain tumors is an important but often overlooked adjunct method of measuring the effectiveness of a carcinogen. A system to estimate malignancy, one that grades 9 tumor characteristics and weights, each according to clinical outcome, was developed. It was found that mixed gliomas grew larger, had a shorter latency, and were significantly more malignant than were other gliomas.
authors.affiliation: The Department of Pathology, The George Washington University, Washington, DC 20037, USA. resbcz@gwumc.edu
authors.forename: B C
authors.initials: BC
authors.lastname: Zook
authors.forename: S J
authors.initials: SJ
authors.lastname: Simmens
authors.forename: R V
authors.initials: RV
authors.lastname: Jones
mesh_terms: D000818:Animals; D001254:Astrocytoma / Q000139:chemically induced / Q000473:pathology; D001932:Brain Neoplasms / Q000139:chemically induced / Q000473:pathology; D002273:Carcinogens / Q000633:toxicity*; D005038:Ethylnitrosourea / Q000633:toxicity*; D005260:Female; D005910:Glioma / Q000139:chemically induced* / Q000453:epidemiology / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology / Q000473:pathology; D009423:Nervous System Neoplasms / Q000139:chemically induced* / Q000453:epidemiology / Q000473:pathology*; D009837:Oligodendroglioma / Q000139:chemically induced / Q000473:pathology; D011846:Radio Waves; D051381:Rats; D017207:Rats, Sprague-Dawley; D013120:Spinal Cord Neoplasms / Q000139:chemically induced / Q000473:pathology; D009626:Terminology as Topic
chemical_list: D002273:Carcinogens; D005038:Ethylnitrosourea