MicroRNAs as novel biomarkers for colorectal cancer: New outlooks

Colorectal cancer is one of the most prevalent cancers with high mortality in the world. MicroRNAs are a class of small non-coding RNAs that regulate gene expression through targeting mRNAs. MicroRNAs involve in many biological and pathological processes such as cell growth, differentiation, apoptosis. etc. Dysregulation of miRNAs expression patterns have been reported in many tumors including Colorectal Cancer. Various studies indicate that miRNAs can be utilized as diagnostic and prognostic biomarkers for evaluation of tumor initiation, development, invasion, metastasis and response to chemotherapeutic drugs. Numerous investigations have also shown dysregulation of miRNAs in tissue samples and body fluids such as serum, plasma and fecal samples from CRC patients. Recently, several studies have demonstrated that miRNAs have regulatory roles in response to anti-cancer drugs and suggested them as predictive factors for successful treatment. In this review, we highlight the facts concerning tumor suppressor miRNAs and oncomiRs in CRC; by emphasizing their importance in different signaling pathways such as the Wnt/β catenin activation, EGFR pathway, (TGF-ß) and the TP53 network and then their potential as biomarker and targets for cancer treatment.