The Role of miRNA in Colorectal Cancer for Early Detection and Potential Clinical Significances

Background: Colorectal cancer (CRC) is currently the third most common cancer in males and the second in females worldwide. Objective: The main objective of the current study was to investigate the possibility of using MicroRNA (miRNA) as potential biomarkers in early detection of CRC. Methodology: It was a case control study. A self-structured questionnaire was used to collect socio-demographic data, medical history and other lifestyle factors. Moreover, blood analysis was used to validate the expression and diagnostic role of miRNA when it comes to CRC. A total of 80 subjects were recruited to participate in the current study (40 cases + 40 healthy controls). For blood analysis, a total RNA was isolated from 200?l of each patient's plasma (four samples 250?l) using the QIAGEN miRNeasy serum/plasma kit. Isolated RNA was stored at -80?C. miRNAs expression was assayed by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) to generate miRNA normalized copy numbers. Relative expression of ten CRC-related miRNAs (miR-21, miR-31, miR-20a, and miR-145, miR-135b and let-7g, miR-10b-5p, miR-215-5p and miR-150-5p, and isomiRs of miR-125b-5p and miR-30a-5p and miR29a) and three CRC-related genes was detected using the SYBR Green quantitative real-time PCR technique. The correlation between gene expression levels and clinic-pathological features was evaluated. Results: Preoperative high plasma miRNA levels were associated with increased recurrence risk for miR-29a (HR ? 2.61 [1.34,5.07], P ? 0.005), and miR-31 (HR ? 4.03 [1.76, 9.24], P ? 0.001). Both plasma miR-31 (AUC: 0.717) and miR-29a (AUC: 0.703) discriminate recurrence from these patients without recurrence. In addition, high levels of miR-31 during surveillance was associated with a three-fold increased risk of recurrence across all time points. Conclusion: Pre-operative plasma miR-29a and 31 are potential CRC prognosis biomarkers. In addition, dynamic postoperative miR-31, and 145 are potential biomarkers for the early detection of recurrence during CRC surveillance.