Abstract: Objective To investigate the potential value of miR-141 as a diagnostic blood biomarker expression level in patients with colorectal cancer(CRC) and its change after radical CRC resection.Methods 75 CRC patients admitted to Affiliated to Medical College of Xi’an Jiaotong University 3201 Hospital from April 2019 to March 2021 were included in the experimental group,and 20 patients who received planned surgery for inguinal hernia during the same period were used as non-cancer control group.Surgical tissue and serum samples of these patients were collected.Microarray analysis was performed for miRNAs with significant expression differences in CRC tissues and serum.Real-time quantitative PCR(qRT-PCR) was used to verify the expression level of miR-141 in serum samples of the patients before surgery and at the 3rd day after surgery,and the relationship between miR-141 and clinicopathological characteristics of CRC patients was analyzed.Results By miRNA microarray analysis, we confirmed that 12 miRNAs were up-regulated simultaneously in tissue and serum samples of CRC patients,among which miR-141 was the most significantly up-regulated.Meanwhile,the relative expression level of miR-141 in serum of CRC group was significantly higher than that of non-cancer control group after qRT-PCR verification[2.50(1.06，3.12)vs.0.97(0.68，1.21)，Z=-5.842，P＜0.05].According to ROC curve analysis, the AUC value of preoperative serum miR-141 for the diagnosis of CRC was 0.927(95%CI:0.862～0.992).When serum miR-141≥1.418, the accuracy of distinguishing between CRC and non-cancer control groups was 90.53%.Combined detection of serum miR-141 could increase the diagnostic AUC value of carcinoembryonic antigen and carbohydrate antigen 199 to 0.944(95%CI：0.899～0.998).For CRC patients, the relative expression level of serum miR-141 after radical resection was significantly lower than that before surgery[1.85(1.29，2.22) vs.2.55(2.07，3.18)，Z=-5.416，P＜0.001].For those who did not receive radical resection, the relative expression level of serum miR-141 after surgery was slightly lower than that before surgery[2.28(1.72，2.74)vs.2.45(2.06，2.85)],but the difference was not statistically significant(Z=-1.917，P=0.055).The expression level of Mir- 141 in serum of CRC patients was correlated with UICC stage and histological grade(P＜0.05).Conclusion Serum miR-141 reflects the pathological changes of CRC patients and can be used as a biomarker for noninvasive diagnosis of CRC.

Key words: serum, miRNAs microarray, colorectal cancer, diagnosis