Evaluation of Differential Expression of MiR-18a and MiR-34a in Plasma Samples of Colorectal Cancer Patients

The early diagnosis of colorectal tumors is one of the most important challenges in cancer management. MiRNAs are a group of non-coding RNAs that regulate posttranscriptional expression of target genes. Dysregulation of miRNAs has been reported in associated with a variety of malignancies, including colorectal cancers. This study aimed to analyze the differential expression of miRNAs in plasma samples of colorectal cancer (CRC) patients to examine their potential value as diagnostic biomarkers. In this case- control study, 74 plasma samples of CRC patients with stage II-IV and 36 healthy controls were collected. miR-18a, miR-34a, miR-181b and miR-146b were selected. The expression level of the miRNAs was assayed by quantitative reverse transcriptase PCR (qRT-PCR). Then, statistical analyzes were performed to determine the relationship between miRNAs expression and clinical-pathological characteristics. The significantly elevated levels of miR-18a and miR-34a were detected in plasma samples compared to the healthy groups (P<0.001). ROC showed an area under the ROC curve (AUC) of 0.85 and P<0.001 for miR-18a, 0.74 and P<0.001 for miR-34a. There were no significant dysregulation of miR-146b and miR-181b between patients and controls (P>0.05). Our results indicated that the expression levels of miR-18a and miR-34a are systematically elevated in CRC plasma samples. It might be helpful to illuminate the molecular mechanisms underlying CRC carcinogenesis and served as tumor-associated biomarkers for diagnosis.