ABSTRACT
Background: Patients with stage II CRC have a varying survival outcome. Therefore, it is critical to identify prognostic biomarkers that can define more aggressive forms of the disease. We assessed the expression levels of five miRNAs that have been previously addressed in relation to the development and progression of solid and hematological tumors. Methods: We measured the expression levels of miR-21, miR-137, miR-145, miR-320 and miR-498in stage II CRC patients from Egypt (124 tissues and 41 blood samples) by quantitative real time PCR (qPCR). The results were correlated with relevant clinicopathological factors, response to treatment and survival rates of the patients. Results: miR-137, miR-145 and miR-320 were significantly reduced in 39.5%, 48.4% and 52.4%; respectively whereas miR-21 and miR-498 were significantly overexpressed in 48.4% and 40.3% of the CRC tissues compared to the control group. In patients' blood, miR-137, miR-145 and miR-320 were significantly reduced in 46.3%, 46.3% and 51. 2%; respectively whereas mir-21 and miR-498 were significantly overexpressed in 46.3% and 43.9% of the cases, respectively. The concordance between tissue and blood was weak for miR-320 and miR-145 (kappa 40-65%), intermediate for miR-498 and miR-137 (kappa 65-75%) and strong for miR-21 (kappa 75-85%). In univariate analysis performance status, over-expression of miR-21 and miR-498 and reduced miR-137, miR-145, and miR-320 associated significantly with reduced DFS and OS. However, in multivariate analysis, miR-498 and miR-320 were independent prognostic factors for DFS whereas miR-21 was independent prognostic factors for OS. Conclusions: miRNAs play an important role in the development and progression of stage II CRC. A five markers panel (miR-21, miR-498, miR-137, miR-145 and miR-320) can predict recurrence and survival in stage II CRC patients from Egypt (AU)