Abstract: OBJECTIVE： To investigate expressions of microRNA miR-653-5p in the serum of colon cancer patients and their clinical significance. METHODS： From January 2019 to January 2020，76 colon cancer patients who were treated in the First People’s Hospital of Shangqiu City were selected as the experimental group，and 76 healthy physical examiners in the same period were selected as the observation group. From the collection of 5 mL of fasting venous blood from the subjects，serum miRNA was extracted. Real-time quantitative fluorescence PCR (qPCR) was used to detect expression levels of miR-653-5p，and their differences between the two groups were compared. According to the relative expression level of miR-653-5p，the colon cancer patients in the experimental group were divided into high and low expression groups，and the correlation between miR-653-5p expression and the clinicopathological indicators of colon cancer were analyzed. The clinical diagnostic value of miR-653-5p was analyzed by using the receiver operating characteristic curve (ROC). Kaplan-Meier and multivariate COX regression were used to analyze factors influencing colon cancer survival prognosis. RESULTS： The relative expression level of miR-653-5p in the serum of the control group was 0.622±1.319，and was 0.471±1.076 for the patients，which was significantly lower than that in the control group (P<0.01). There were no significant correlations between the expression levels of miR-653-5p and the sex，age，tumor location and size of colon cancer patients (P>0.05)，but they were related to clinical T stages，distant metastasis，lymph node metastasis，vascular cancer thrombus and tumor differentiation (all P<0.01). The area under the curve of miR-653-5p for clinical diagnosis of colon cancer was 0.823 (P<0.01)，the cut-off value was 0.498，the sensitivity was 80.26%，and the specificity was 82.89%. The Kaplan-Meier curve showed that the survival rate of colon cancer patients in the high-expression group of miR-653-5p was significantly higher than that in the low-expression group (P<0.01). COX regression analysis showed that miR-653-5p expression levels，clinical T stages，distant metastasis，lymph node metastasis，and tumor differentiation were independent risk factors affecting the prognosis and survival of colon cancer patients (all P<0.01). CONCLUSION： The expression levels of miR-653-5p in the serum of colon cancer patients were significantly down-regulated. Our results suggest that miR-653-5p may be a useful and novel biomarker for the diagnosis and prognosis evaluation of colon cancer.

Key words: colorectal cancer, miR-653-5p, pathological indicators, diagnosis, prognosis