Loss of Circulating Exosomal miR-92b is a Novel Biomarker of Colorectal Cancer at Early Stage

Early diagnosis of colorectal cancer (CRC) is clinically critical but technically challenging, especially in a minimal-invasive way. Emerging evidence suggests that exosome-encapsulated microRNAs (miRNAs) is a kind of promising cancer biomarker. Here we investigated the predictive potential of exosomal miR-92b in plasma samples obtained from 114 participants [40 CRC, 22 colorectal adenomas (CA), 52 non-neoplasm controls (NC)] by RT-qPCR. We found that exosomal miR-92b level was significantly down-regulated in CRC patients compared with CA and NC patients, especially in CRC at stage II, regardless of lymph node metastasis and invasive depth. The AUC in distinguishing CRC, CA and NC from each other ranged from 0.631 to 0.793, while a higher AUC of 0.830 was achieved in differentiating CRC at clinical stage II/III from NC individuals. Additionally, a logistic model integrating miR-92b with age showed a significantly improved accuracy in distinguishing CRC patients from NC (AUC increased from 0.793 to 0.867). Taken together, our findings indicated that decreased expression of exosome-derived miR-92b in plasma is a promising biomarker for early detection of CRC.