Abstract: Objective To explore the relationship between preoperative peripheral blood MicroRNA-21(miR-21),vascular endothelial growth factor(VEGF),carbohydrate antigen 19-9(CA19-9) and clinical staging,postoperative recurrence,metastasis in patients with colorectal cancer(CRC).Methods A total of 62 patients with CRC treated in the hospital were enrolled as CRC group between October 2019 and October 2020,while other 62 healthy controls(HC) without CRC by laboratory and imaging examinations during the same period were enrolled as HC group.The relative expression level of peripheral blood miR-21 in both groups was detected by real-time fluorescence quantitative PCR(qRT-PCR).The level of preoperative VEGF in both groups was detected by enzyme-linked immunosorbent assay.The level of preoperative CA19-9 in both groups was detected by chemiluminescence method.All were followed up for 12 months after surgery to record postoperative recurrence and metastasis.The relationship between preoperative peripheral blood miR-21,VEGF,CA19-9 levels and clinical staging in CRC patients was analyzed by Spearman correlation analysis.The predictive value of miR=21,VEGF and CA19=9 for recurrence and metastasis of CRC was detected by receiver operating characteristic(ROC) curves.Results The relative expression level of miR-21 and levels of VEGF and CA19-9 in CRC group were higher than those in HC group(P＜0.05),which were significantly higher in patients at stages III-IV than stage I-II(P＜0.05).The relative expression level of miR-21 and levels of VEGF and CA19-9 were positively correlated with clinical staging of TNM(r=0.451,0.339,0.307,P＜0.05).In CRC group,relative expression level of miR-21 and levels of VEGF and CA19-9 in patients with recurrence and metastasis were higher than those without recurrence and metastasis(P＜0.05).The area under the ROC curve(AUC) of miR-21 combined with VEGF and CA19-9 for evaluating recurrence and metastasis was 0.843(P＜0.05).Conclusion The levels of preoperative peripheral blood miR-21,VEGF and CA19-9 are correlated with clinical staging of CRC patients.Their combined detection has good predictive value for postoperative recurrence and metastasis of CRC,which can be applied as assessment indexes for preoperative clinical staging and postoperative recurrence metastasis.

Key words: microRNA-21, vascular endothelial growth factor, carbohydrate antigen 19-9, colorectal cancer, clinical staging, postoperative recurrence and metastasis