Abstract: Objective To research the expressions of Sirtuin-1 (SIRT1) in colorectal cancer and normal tissue and the relationship with clinicopathologic features. Methods The expression levels of SIRT1 mRNA and protein were detected respectively by quantitative real-time reverse transcriptase PCR (RT-QPCR) and immunohistochemistry (IHC) in 45 cases of colorectal carcinoma and 30 cases of normal mucous membrane tissue, and the relationships between the expression status and clinicopathologic features were analyzed. Results In colorectal carcinoma, the expression of SIRT1 mRNA were higher than that in control group ［M(QR): 2.488(3.447) vs. 1.563(2.867), Z=-2.304, P＜0.05］, so was the protein level (71.1% vs. 43.3%, χ²=5.787, P=0.029). The expression of SIRT1 was associated with lymph node metastasis (RT-QPCR: Z=-2.160, P=0.031; IHC: P=0.043), neoplasm stages (RT-QPCR: Z=-2.411, P=0.016; IHC: P=0.008), and might associated with the tissue differentiation (RT-QPCR: χ²=10.864, P=0.004; IHC: P=0.322). On the other hand, no significant differences were observed regarding age, sex, tumor size, gross type, depth of invasion, tumor site and distant metastasis. Conclusion The expression of SIRT1 in colorectal cancer is higher than that in control group, the high level of SIRT1 is related to the tumorigenesis and progression of colorectal cancer as well as correlated with prognosis in colorectal cancer.

Key words: Colorectal neoplasms, Polymerase chain reaction, Immunohistochemistry, Sirtuin 1