Multiple event or recurrence after transurethral resection is an important characteristic of superficial bladder tumors. were performed using analysis of variance and Fisher’s PLSD GW2580 inhibitor database test. Epithelial cells of normal bladder in the control organizations and those of diffuse hyperplasia, which was a reversible switch at 4 weeks, indicated no telomerase activity. In contrast, telomerase activity significantly improved in the stage after nodular hyperplasia, an irreversible switch at eight weeks, elevated with carcinogenesis then. However, telomere length was still preserved by the 12th week, and was GW2580 inhibitor database shortened at 18 and 24 weeks. These results suggest that telomerase activation is probably induced independent of telomere shortening during bladder carcinogenesis in the rat, and might be a biological tumor marker of irreversible preneoplastic lesions, which evolve into bladder tumors in the rat. strong class=”kwd-title” Keywords: Bladder carcinogenesis, Telomerase, Telomere, BBN, Hyperplasia REFERENCES 1. ) Feng J. , Funk W. D. , Wang S. S. , Weinrich S. L. , Avilion A. A. , Chiu C. P. , Adams R. R. , Chang E. , Allsopp R. C. , Yu J. , Le S. , West M. D. , Harley C. B. , Andrews W. H. , Greider C. W. and Villeponteau B.The RNA component of human telomerase . Science , 269 , 1236 C 1241 ( 1995. ). [PubMed] [Google Scholar] 2. ) Shay J. W. and Bacchetti S.A survey of telomerase activity in human cancer (Review) . Eur. J. Cancer , 33 , 787 C 791 ( 1997. ). [PubMed] [Google Scholar] 3. ) Kinoshita H. , Ogawa O. , Kakehi Y. , Mishina M. , Mitsumori K. , Itoh N. , Yamada H. , Terachi T. and Yoshida O.Detection of telomerase activity in exfoliated cells in urine from patients with bladder cancer . J. Natl. Cancer Inst. , 89 , 724 C 730 ( 1997. ). [PubMed] [Google Scholar] 4. ) Yoshida K. , Sugino T. , Tahara H. , Woodman A. , Bolodeoku J. , Nargund V. , Fellows G. , Goodison S. , Tahara E. and Tarin D.Telomerase activity in bladder carcinoma and its implications for non\invasive diagnosis by detection of exfoliated cancer cells in urine . Cancer , 79 , 362 C 369 ( 1997. ). [PubMed] [Google Scholar] 5. ) Ito N.Early changes caused by N\butyl\N\(4\hydroxybutyl)nitrosamine in the bladder epithelium of different animal CD117 species . Cancer Res. , 36 , 2528 C 2531 ( 1976. ). [PubMed] [Google Scholar] 6. ) Kakizoe T. , Hasegawa F. , Kawachi T. and Sugimura T.Isolation of transitional epithelial cells from the rat urinary bladder . Invest. Urol. , 15 , 242 C 244 ( 1977. ). [PubMed] [Google Scholar] 7. ) Nozawa K. , Kurumiya Y. , Yamamoto A. , Isobe Y. , Suzuki M. and Yoshida S.Up\regulation of telomerase in primary cultured rat hepatocytes . J. Biochem. , 126 , 361 C 367 ( 1999. ). [PubMed] [Google Scholar] 8. ) Kamata S. , Kageyama Y. , Yonese J. and Oshima H.Significant telomere reduction in human superficial transitional cell carcinoma . Br. J. Urol. , 78 , 704 C 708 ( 1996. ). [PubMed] [Google Scholar] 9. ) Lin Y. GW2580 inhibitor database , Miyamoto H. , Fujinami K. , Uemura H. , Hosaka M. , Iwasaki Y. and Kubota Y.Telomerase activity in human bladder cancer . Clin. Cancer Res. , 2 , 929 C 932 ( 1996. ). [PubMed] [Google Scholar] 10. ) Heine B. , Hummel M. , Muller M. , Heicappell R. , Miller K. and Stein H.Non\radioactive measurement of telomerase activity in human bladder cancer, bladder washings, and in urine . J. Pathol. , 184 , 71 C 76 ( 1998. ). [PubMed] [Google Scholar] 11. ) Kyo S. , Kunimi K. , Uchibayashi T. , Namiki M. and Inoue M.Telomerase activity in human urothelial tumors . Am. J. Clin. Pathol. , 107 , 555 C 560 ( 1997. ). [PubMed] [Google Scholar] 12. ) Rabat M. A. , Lahat N. , Gazawi H. , Resnick M. B. , Sova Y. , Ben\Ari G. , Cohen M. and Stein A.Telomerase activity in patients with transitional cell carcinoma: a preliminary study . Cancer , 85 , 919 C 924 ( 1999. ). [PubMed] [Google Scholar] 13. ) Kavaler E. , Landman J. , Chang Y. , Droller M. J. and Liu B. C.Detecting human bladder carcinoma cells in voided urine samples by assaying for the presence of telomerase activity . Cancer , 82 , 708 C 714 GW2580 inhibitor database ( 1998. ). [PubMed] [Google Scholar] 14. ) Montalto M..