Abstract: Abstract: Objective To detect the expression and significance of serum miRNA- 183 and TK1 in patients with colorectal cancer, and the mechanism thereof. Methods Fifty-two serum samples of colorectal cancer patients and paired health serum samples were collected. The expression of miRNA-183 was detected by real-time quantitative PCR, and TK1 was detected by Western blot enhanced chemiluminescence assay. The correlation between miRNA-183 and TK1 and their relations with the clinicpathologic characteristics were analyzed. Results The serum miRNA- 183 expression was significantly higher in colorectal cancer group than that in normal control group (P < 0.01). The expression of serum miRNA- 183 was significantly higher in stage Ⅲ-Ⅳ group than that in stage Ⅰ-Ⅱ group (P < 0.01). There was more significant increase in serum miRNA- 183 in lymphatic metastasis group than that without lymphatic metastasis group (P < 0.01). Receiver operating characteristic (ROC) curve showed that of there was a diagnostic value for serum miRNA- 183 in colorectal cancer, with an optimal value of 1.15. The diagnostic sensitivity and specificity were 78.8% and 67.3%, and the positive predictive value and negative predictive value were 78.9% and 70.2%. The serum TK1 expression was also higher in colorectal cancer group compared with that of normal control group (P < 0.01). And the TK1 expression was also higher in stage Ⅲ-Ⅳ group than that in stage Ⅰ-Ⅱ group (P < 0.01). Furthermore, miRNA-183 expression was positively correlated with TK1 expression (rs=0.692, P < 0.01). Conclusion The serum expression levels of miR-183 and TK1 may act as tumor markers for early colorectal cancer diagnosis, and also can be used to predict the malignant degree and prognosis of colorectal cancer.

Key words: colonic neoplasms, microRNAs, thymidine kinase, serum, colon cancer, miR-183