ObjectiveTo provide the obstetrician-gynecologist with the following: 1) basic concepts of telomere shortening and telomerase acitvation and their relation to cellular immortalization and cancer, 2) an overview of potential uses of telomerase activity in cancer diagnosis, assessment of prgnosis, and the development of new anticancer therapeutic approaches, and 3) a review of the literature on telomerase activity in gynecologic cancers.Data SourcesA computerized search for articles published in which telomerase or telomerases were included as a subject heading or a textword was performed using the Ovid Search Software (Ovid Technologies Inc., New York, NY). The search was conducted of the following databases of the National Library of Medicine and the National Cancer Institute: MEDLINE January 1966 to May 1997, HealthSTAR January 1975 to May 1997, AIDSline January 1980 to May 1997, and CancerLit January 1980 to May 1997. Additional sources were identified through cross-referencing.Methods of Study SelectionAll sources identified were reviewed with particular attention to human application, specifically in gynecologic cancers.Tabulation, Integration, and ResultsA total of 304 references was identified. Each reference was reviewed to determine the relevant contribution to the basic understanding of the role of telomerase in cellular immortalization and the development of cancer, potential uses of telomerase measurement in cancer, gynecologic applications, and potential use of telomerase inhibitors in cancer therapy.ConclusionTelomerase activity might be a valuable diagnostic and prognostic toll in gynecologic and other types of cancer, and telomerase inhibition might prove to be a significant therapeutic approach for some types of cancer. Better understanding of the relation between telomerase activation, tumor suppressor genes, and oncogenes might clarify several aspects of early tumorigenesis and result in development of novel approaches to early cancer detection and prevention.