Affiliations: [a] Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, Brno, Czech Republic | [b] Department of Gastroenterology, Masaryk Memorial Cancer Institute, Brno, Czech Republic | [c] Central European Institute of Technology, Masaryk University, Kamenice, Brno, Czech Republic
Correspondence:
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Corresponding author: Ondrej Slaby, Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic. Tel.: +420 543136902; E-mail: on.slaby@gmail.com.
Abstract: Background:Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the world. Therefore, there is a high demand for cost-effective and non-invasive biomarkers that would enable an early detection of asymptomatic and curable disease with high sensitivity and specificity. Objective:The main objective of this study was to investigate the potential of circulating miRNAs as biomarkers of CRC. Methods:Total RNA enriched for small RNAs was isolated from 100 sera of patients with CRC and 30 sera of healthy donors. The expression levels of miR-17-3p, miR-29a, miR-92a and miR-135b were determined using quantitative real-time PCR. The average expression levels of particular miRNAs were normalized to miR-16 levels and statistically evaluated. Results:Using Mann-Whitney U test, no significant differences were observed in miR-17-3p (P=0.18), miR-29a (P=0.14) and miR-92a (P=0.60) levels between sera of CRC patients and controls. The levels of miR-135b in serum were too low to be quantified accurately. Subsequently, we tried to correlate expression levels of analyzed miRNAs to clinical-pathological features of CRC patients. Only levels of mir-29a were correlated with the clinical stage (P=0.04). Expression levels of the other miRNAs were correlated neither with the clinical stage, nor with the grade. Conclusions:Interestingly, our results are contradictory to previous studies performed on the CRC patients from Chinese population, providing an evidence against usage of serum miR-17-3p, miR-29a, miR-92a and miR-135b as new biomarkers for early detection of CRC.
