Fecal miR-29a and miR-224 as the noninvasive biomarkers for colorectal cancer.

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.