Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Overexpression of cyclin D1 and cyclin E in 1,2-dimethylhydrazine dihydrochloride-induced rat colon carcinogenesis | J. Vet. Sci. 2000 1 2 121-126 OURNAL OF Veterinary Science Overexpression of cyclin D1 and cyclin E in 1 2-dimethylhydrazine dihydrochloride-induced rat colon carcinogenesis Kwon Hur Jung-Rae Kim Byung-Il Yoon1 Jung-Keun Lee Jae-Hoon Choi Goo-Taeg Oh2 and Dae-Yong Kim Department of Veterinary Pathology College of Veterinary Medicine and School of Agricultural Biotechnology Seoul National University Suwon 441-744 Korea National Institute of Health and Sciences Tokyo 158-8501 Japan 2Korea Research Institute of Bioscience and Biotechnology Taejon 305-333 Korea Deregulation of G1 cyclins has been reported in several human and rodent tumors including colon cancer. To investigate the expression pattern of G1 cyclins in 1 2-dimethyl-hydrazine dihydrochloride DMH -induced rat colon carcinogenesis we studied the expression of cyclin D1 and cyclin E by quantitative reverse transcription-polymerase chain reaction RT-PCR analysis and immunohistochemistry IHC . The mRNA level of cyclin D1 was increased in adenocarcinomas but not significantly in adenomas when compared with normal rat colonic mucosa p . The cyclin E mRNA level was increased in adenomas and in adenocarcinomas p . The PCNA mRNA level was also increased in adenomas and in adenocarcinomas p . Immunohistochemical staining revealed exclusive nuclear staining of the neoplastic cells for cyclin D1 cyclin E and PCNA. Cyclin D1 expression was detected in of the adenomas and in of the adenocarcinomas examined whereas cyclin E expression was detected in of the adenomas and in of the adenocarcinomas. Overall cyclin D1 cyclin E and PCNA expression was significantly increased at both the mRNA and protein levels in normal colonic mucosa adenomas and adenocarcinomas but there was no significant difference in the degree of expression of these genes in adenomas and adenocarcinomas. Our results indicate that the overexpression of cyclin D1 and cyclin E