Circulating miR-17-3p, miR-29a, miR-92a and miR-135b in serum: Evidence against their usage as biomarkers in colorectal cancer

摘要

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the world. Therefore, there isna high demand for cost-effective and non-invasive biomarkers that would enable an early detection of asymptomatic and curablendisease with high sensitivity and specificity.nOBJECTIVE: The main objective of this study was to investigate the potential of circulating miRNAs as biomarkers of CRC.nMETHODS: Total RNA enriched for small RNAs was isolated from 100 sera of patients with CRC and 30 sera of healthyndonors. The expression levels of miR-17-3p, miR-29a, miR-92a and miR-135b were determined using quantitative real-timenPCR. The average expression levels of particular miRNAs were normalized to miR-16 levels and statistically evaluated.nRESULTS: Using Mann-Whitney U test, no significant differences were observed in miR-17-3p (P = 0.18), miR-29a (P =n0.14) and miR-92a (P = 0.60) levels between sera of CRC patients and controls. The levels of miR-135b in serum were too lownto be quantified accurately. Subsequently, we tried to correlate expression levels of analyzed miRNAs to clinical-pathologicalnfeatures of CRC patients. Only levels of mir-29a were correlated with the clinical stage (P = 0.04). Expression levels of thenother miRNAs were correlated neither with the clinical stage, nor with the grade.nCONCLUSIONS: Interestingly, our results are contradictory to previous studies performed on the CRC patients from Chinesenpopulation, providing an evidence against usage of serum miR-17-3p, miR-29a, miR-92a and miR-135b as new biomarkers fornearly detection of CRC.