Serum miR-21 and miR-210 as promising non-invasive biomarkers for the diagnosis and prognosis of colorectal cancer

Objective: this study aimed to investigate the expression and clinical significance of miR-21 and miR-210 in serum of patients with colorectal cancer (CRC). Methods: the expression levels of serum miR-21 and miR-210 in 40 CRC patients (CRC group) and 20 healthy patients (control group) were measured by qRT-PCR. Correlation analysis was performed of the relationship between serum miR-21 and miR-210 levels with clinical characteristics, including gender, age, tumor location, tumor size, tumor stage, local invasion and TNM staging. The expression levels of miR-21 and miR-210 in the CRC group were separately measured before and after surgery. ROC analysis was performed to evaluate the diagnostic value of miR-21 and miR-210. Results: serum miR-21 and miR-210 in the CRC group were much higher than those in the control group. Meanwhile, the levels of serum miR-21 and miR-210 were closely related to tumor size (p = 0.028, p = 0.047), lymphatic metastasis (p = 0.038, p = 0.028), TNM staging (p = 0.014, p = 0.047) and tumor stage (p = 0.014, p = 0.017), but independent of gender, age and tumor location. In addition, serum miR-21 and miR-210 in the CRC group (n = 18) after surgery were lower than those before surgery (p < 0.001). ROC curves showed that miR-21 (AUC = 0.863) and miR-210 (AUC 0.818) both had diagnostic efficacy in CRC patients. Conclusion: miR-21 and miR-210 can be used as novel noninvasive biomarkers for CRC diagnosis and prognosis.