Abstract
BACKGROUND: Colorectal cancer (CRC) is one of the most common causes of cancer-related death around the world. MicroRNAs (miRNAs) are small non-coding RNAs that often are abnormally expressed in tumors. Detection and quantitation of miRNAs may provide information for the screening and early diagnosis of CRC. OBJECTIVES: The objective of our study was to determine whether fecal microRNAs (miR-29a, miR-145, miR-223, miR-224) could be used as biomarkers for the screening and early diagnosis of colorectal cancer. METHODS: We carried out a retrospective analysis of the miRNAs in fecal samples from 80 CRC patients and 51 normal controls. The levels of 4 miRNAs (miR-29a, miR-145, miR-223, and miR-224) were quantitated using the SYBR Green miScript PCR system and 2( - Δ Δ Ct) method. RESULTS: Our data indicated that the expression levels of miR-29a (p< 0.001), miR-223 (p< 0.001) and miR-224 (p< 0.001) are significantly lower in feces from CRC patients than these from normal volunteers, whereas their miR-145 levels are not significantly different (p= 0.59). Interestingly, the level of miR-29a (p< 0.001) in feces from individuals with rectum cancer is also significantly higher than that from patients with colon cancer. CONCLUSION: There are reduced expression of miR-29a, miR-223, and miR-224 in the feces from the CRC patients, which could be an informative biomarker for screening and early diagnosis of CRC.