Serum miR-218 is a Potential Biomarker in the Diagnosis of Colorectal Cancer

Background: Our study was designed to explore the diagnostic role of serum microRNA-218 (miR-218) in colorectal cancer (CRC).Methods: Serum level of miR-218 was measured in 117 CRC samples and 88 normal controls using quantitative reverse transcription (qRT-PCR). Chi-square test was performed to assess the relationships between miR-218 expression and clinical characteristics of CRC patients. The receiver operating characteristic (ROC) analysis was established to investigate the diagnostic significance of miR-218 in CRC with the area under ROC curve (AUC).Results: MiR-218 was found to be weekly expressed in CRC serum samples compared with healthy controls (P < 0.001). And the down-regulation of miR-218 shared close relationships with lymph node metastasis (P = 0.013), vascular invasion (P = 0.020) and TNM stage (P = 0.031). However, age, tumor size and gender had no significant influence on miR-218 expression (P > 0.05). According to the ROC curve, miR-218 yielded an AUC value of 0.897 and an optimal cutoff point value of 0.021, providing a 83.8% sensitivity and a 78.4% specificity. Conclusion: In summary, decreased expression of serum miR-218 was detected in CRC patients and the expression of miR-218 was a diagnostic marker in CRC.