Integrated characterization and validation of the prognostic significance of microRNA-200s in colorectal cancer.

Background: Accumulating evidence has demonstrated that microRNA-200s (miR-200a, miR-200b and miR-200c) could serve as promising molecular biomarkers for cancer prognosis. Nevertheless, the associations between miR-200s expression and colorectal cancer (CRC) prognosis remain controversial. Methods: We applied two mainstream approaches combining meta-analysis and bioinformatics analysis to answer whether miR-200s were associated with the prognosis of CRC patients and why miR-200s could be used as prognostic biomarkers for CRC. Results: Consequently, low expression of miR-200s was associated with unfavorable overall survival (OS) in CRC patients (HR: 1.09; 95% CI 1.01-1.17; P = 0.025). According to the subgroup analysis, the prognostic role of miR-200s was more significant for tissue samples, large samples, American patients and miR-200a subgroups. Then the target genes of miR-200s were predicted and applied for functional enrichment analyses. The results showed that the target genes of miR-200s were mainly enriched into some vital ontology subjects such as regulation ability, key cell structures and binding function. Moreover, a series of important signaling pathways were identified, which were significantly linked with the initiation and progression of CRC. Additionally, a proteinprotein interaction (PPI) network of miR-200s targets was constructed to screen hub genes and modules. The identified hub genes and modules were validated to be highly involved in the occurrence and development of CRC. Conclusions: Current evidences revealed that miR-200s could be promising biomarkers for CRC prognosis. However, the findings still need to be validated with more larger-scale prospective studies and biological experiments before miR-200s could be applied into clinical application.