Abstract: AIM To assess the diagnostic value of circRNAs in detection of tumors through a systematic review.METHODS Articles were searched in CNKI,WanFang database,PubMed and Web of Science databases up to May 5,2017 with the Title/Abstract words ("circular RNA" or "circRNA" and "cancer" or "tumor" or "carcinoma").Two investigators extracted the data and assessed the quality of included articles using the Newcastle-Ottawa Scale (NOS) independently.RESULTS Thirty-two studies were finally included,which covered hepatocellular carcinoma,gastric cancer,colorectal cancer,and other cancers.The NOS scores of all included studies were 7.Among them,few studies clearly indicated that circRNAs can serve as potential biomarkers and provided the ROC curve,AUC (area under the curve),sensitivity,and specificity.CONCLUSION CircRNAs have significant potential to serve as biomarkers for the diagnosis of tumors.Further studies with larger number of patients will be needed to validate these findings.