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Abstract Colorectal cancer (CRC) has been one of the most commonly diagnosed cancers in global. The differential expression profiles of microRNAs (miRNAs) in CRC plasma of patients have the potential to serve as a diagnostic biomarker. We conducted a four-stage study to identify the potential plasma miRNAs for CRC detection. In the initial screening phase, Exiqon panel (miRCURY-Ready-to-Use-PCR-Human-panel-I + II-V1.M) including 3 CRC pools and 1 normal controls (NCs) pool were applied to acquire miRNA profiles. In the training stage (30 CRC VS. 30 NCs) and testing stage (79 CRC VS. 76 NCs), quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to conduct candidate miRNA profiles. Then the identified miRNAs were verified in external validation stage (30 CRC VS. 26 NCs). Expression levels of identified miRNAs were assessed in tissue samples (24 pairs) and plasma exosomes (18 CRC VS. 18 NCs). Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic accuracy. Seven miRNAs (miR-103a-3p, miR-127-3p, miR-151a-5p, miR-17-5p, miR-181a-5p, miR-18a-5p and miR-18b-5p) were significantly overexpressed in CRC compared with NCs. Area under the ROC curve of the seven-miRNA signature was 0.762, 0.824 and 0.895 for the training, testing and the external validation stages, respectively. Additionally, miR-103a-3p, miR-127-3p, miR-17-5p and miR-18a-5p were discovered significantly up-regulated in CRC tissues; while miR-17-5p, miR-181a-5p, miR-18a-5p and miR-18b-5p were significantly elevated in CRC plasma exosomes. In conclusion, we established a seven-miRNA signature in the peripheral plasma for CRC detection. Highlights • We investigated plasma miRNA profiles of CRC in a four-stage process and present a seven-miRNA signature in discriminating CRC. • We found that miR-103a-3p, miR-127-3p, miR-17-5p and miR-18a-5p were significantly up-regulated in CRC tissues. • We found that miR-17-5p, miR-181a-5p, miR-18a-5p and miR-18b-5p were significantly elevated in CRC plasma exosomes. • We discovered that plasma miR-26a-5p was only up-regulated in colon cancer patients but not in rectal cancer. • We found none of the seven miRNAs demonstrated significant different expression in patients with stage III + IV compared to those with stage I + II. • We found that no difference of the above seven plasma miRNA between left-sided and right-sided CRC. [ABSTRACT FROM AUTHOR]