Abstract: Objective To explore the expression and clinical significance of miR-210 in serum of patients with colorectal cancer(CRC). Methods The expression levels of miR-210 in serum of 48 CRC patients(CRC group) and 40 healthy people(control group) were tested by quantitative real-time PCR (qRT-PCR), followed by the analysis on the association of miR-210 expression levels with clinicopathological characteristics. The expression levels of miR-210 in serum of 12 patients in CRC group were determined before operation, at one month after operation and recurrence after operation. The expression levels of CA199 and CEA of the two groups were tested. The diagnostic value for CRC was evaluated by comparing the ROC curves of miR-210, CA199 and CEA. Results The expression level of serum miR-210 in CRC group was higher than that in control group, and the expression level of miR-210 in CRC group was associated with tumor size, local invasion, lymph nodes metastasis and clinical TNM stage (all P < 0.05). However, there was no significant correlation between miR-210 expression and gender, age, tumor type and differentiation(all P > 0.05). The expression levels of miR-210 in serum of 12 patients in CRC group at the first month after operation was lower than those before operation(P < 0.001), and its expressions in postoperative recurrence patients of CRC group were higher than that at the first month after operation(P < 0.001). ROC curve analysis showed that AUC for miR-210 was 0.835, which was higher than that of CEA(AUC: 0.672, Z=2.230, P < 0.05) and CA199(AUC: 0.651, Z=2.427, P < 0.05), while the diagnostic specificity, sensitivity, cutoff value, positive predictive value, negative predictive value and accuracy rate of miR-210 were 82.5%, 70.8%, 38.31, 82.9%, 70.2% and 76.1%, respectively. Conclusion Circulating miR-210 might be used as a novel non-invasive biomarker for early diagnosis of CRC.

Key words: Serum, Biomarkers, Colorectal cancer, MiR-210