Background: Colorectal cancer (CRC) is the second leading cause of cancer deaths worldwide. The current method of clinical screening is mainly based on colonoscopy. However, many CRC patients are unwilling to undergo colonoscopy because of the high procedure cost and the discomfort during examination. Therefore, it appears necessary to find novel and non-invasive biomarkers that would improve CRC early detection. MicroRNAs (miRNAs) are a class of non-coding RNAs with critical regulatory roles in fundamental cellular processes, such as proliferation, migration, and apoptosis. They can act as potential oncogenes or tumor suppressors in cancer development. Numerous studies have shown significant differences in miRNAs expression in serum or plasma of CRC patients and healthy subjects. Thus, the potential use of circulating miRNAs as diagnostic biomarkers in CRC seems to be a fast and relevant alternative to traditional and invasive methods. Here, we reviewed selected studies which identified dysregulated circulating miRNAs in CRC and evaluated their diagnostic value.

Methods: This meta-analysis study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The articles were searched in online databases such as PubMed, Google Scholar to identify all eligible studies that evaluated the diagnostic value of miRNAs for CRC. Then we explored the diagnostic accuracy of each miRNA using the random-effects model to estimate the pooled sensitivity (Se), specificity (Sp), Positive likelihood ratio (PLR) and Negative likelihood ratio (NLR) and the area under the curve (AUC), along with their corresponding 95% confidence intervals (CIs). The statistical analyses were performed using the Review Manager (Revman) 5.4 software and the Meta Disc software.

Results: Thirteen studies involving five microRNAs were included in our analysis. Our results suggested that serum miR-29a levels showed great potential as a high diagnostic biomarker for CRC. The overall pooled sensitivity, specificity, area under the curve (AUC), PLR and NLR of circulating miR-29a were 69.75%, 88.25%, 0.8351, 5.93 and 0.342 respectively.

Conclusion: miRNAs have become increasingly recognized molecular tools in CRC diagnosis. According to our results, circulating miR-29a level has potential value for early detection and might be used as a novel diagnostic biomarker for CRC in combination with other biomarkers.

Citation Format: Sofia Fathi, Fadila Guessous, Mehdi Karkouri. Emerging microRNAs as biomarkers for colorectal cancer diagnosis: A meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1484.