Role of circulating micro-RNA-21 as a noninvasive biomarker for detection of colorectal cancer

Objective To assess serum micro-RNA-21 (miR-21) expression level as a stable blood-based biomarker for colorectal cancer (CRC). Background CRC represents the third most common tumor worldwide with male predominance, with significant morbidity and mortality despite the recent therapeutic improvements. Therefore, a noninvasive diagnostic marker with good sensitivity and specificity is very important, which leads to better clinical outcomes. MiR-21 is an oncogenic miRNA that modulates the expression of multiple cancer-related target genes. MiR-21 expression was upregulated in the serum and in the malignant tissues in relation to the normal tissues. Its elevated level is claimed to be associated with poor survival and poor response to treatment. Patients and methods This cross-sectional study was carried on 50 patients and measured their serum miR-21 (CYBR Green). The cases group comprised 20 consecutive patients with CRC proved by colonoscopy and histopathological biopsy examination, the second group comprised 20 patients with colorectal polyps with no malignant transformation proved by histopathological examination, and the third group included 10 patients with normal colonoscopy finding as the control group. The studied cases were attending the Endoscopy Unit Menoufia University Hospital and Nasser Institute. The three groups agreed to written consent to participate in this study after the approval of the local ethical committee. Results Serum miR-21 expression was significantly upregulated in the cases group of patients with CRC compared with the other groups, with P value less than 0.001, showing sensitivity of 85% and specificity of 83.3% at a cutoff point of −2.31. Conclusion Mi-RNA-21 shows upregulation in the serum in CRC cases, with statistically significant difference compared with the control group and the polyp group, showing promising results as a noninvasive biomarker of CRC.