Abstract: BACKGROUND AND AIM: To explore the role of JC virus early region gene encoding product large tumor antigen(T-Ag) and the interaction between T-Ag and tumor suppressors P53 and pRb in human colorectal adenocarcinoma. MATERIALS AND METHODS: The expression of JCV T-Ag and P53 and pRb proteins were evaluated by immunohistochemistry PV method in 77 cases of human colorectal adenocarcinoma , 20 colorectal adenomas and 20 normal colorectal mucosa. RESULTS: The positive rate of JCV T-Ag 、P53 and pRb proteins were 36.4％、61.0％and 55.8％,respectively, in 77 cases of human colorectal adenocarcinoma , and there was an obvious difference when compared with colorectal adenomas and normal colorectal mucosa (P<0.05).There was no statistically significant links between the presence of T-Ag and pT, pN, pM or differentiation degree(P<0.05). P53 was closely correlated to differentiation degree(P<0.05),but was not correlated to the age, site, p-TNM and lymph node metastasis(P>0.05). pRb was closely correlated to p-TNM and lymph node metastasis(P<0.05).There was statistically significant correlation among the expression of T-Ag and P53、pRb protein (r=0.272，r=0.237，P<0.05). CONCLUSION: JCV was closely related to colorectal adenocarcinoma. Its encoding product in the large T antigen played an important role in the carcinogenic process.

Key words: JC virus, large tumor antigen, P53, pRb, colorectal adenocarcinoma