INCREASED TELOMERASE ACTIVITY AND ABSENCE OF P53 MUTATION IN OLIGOASTROCYTOMAS INDUCED BY N-ETHYL-N-NITROSOUREA IN RATS

The question of whether the changes in telomerase activity and/or the alteration of the p53 gene are involved in the development of oligo-as trocytomas induced by N-ethyl-N-nitrosourea (ENU) in rats was addresse d. Telomerase activity levels of oligo-astrocytomas, including early n eoplastic lesions, were significantly increased as compared to the nor mal controls, correlating with the degree of malignancy. In contrast, no mutations of p53 exons 5-7 were found in early neoplastic lesions o r oligo-astrocytomas. These results indicate that the activation of te lomerase occurs during astrocytoma carcinogenesis and contributes to t he development of brain tumors, but the alterations of p53, at least o n exons 5-7, may not be involved in this process. (C) 1998 Elsevier Sc ience Ireland Ltd.