Down-regulation of fecal miR-143 and miR-145 as potential markers for colorectal cancer

Objectives: To detect 4 MicroRNA (miRNA) in the stool samples of colorectal cancer (CRC) patients to determine whether these miRNAs could be biomarkers in CRC screening or treatment. Methods: A retrospective comparison study was carried out in the Department of Colorectal Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China from September 2009 to March 2011. We detected 4 miRNAs (miR-143, miR-145, miR-21, and miR-106a) in the stool samples of 38 CRC patients and 13 healthy individuals. Total RNA from the stool samples was extracted using the EZNA (TM) stool RNA kit R6828-01. The miRNA quantification was carried out using TaqMan miRNA assays and the TaqMan(circle) Gene Expression Master Mix. Results: The expression levels of miR-143 and miR-145 in the stool of the CRC patients were lower than in those of the healthy persons (p<0.005, median of 2(-Delta Delta CT)). No statistically significant difference was found in the expression levels of both miR-21 and miR-106a between the stool of CRC patients and those of the healthy persons (p>0.05). Conclusion: The detection of fecal miRNAs is a potential method for CRC diagnosis or screening. Particularly, the down-regulation of fecal miR-143 and miR-145 could be a potential marker for CRC.