Emerging role of microRNA-21 in colorectal cancer.

Colorectal cancer (CRC) is one of the most common types of cancers worldwide. In spite of much progress in surgery, chemotherapy and molecular targeted therapy, the mortality rate has only decreased slightly over the past years. MicroRNAs are 18-25 nucleotide, noncoding RNA molecules that regulate the translation of many genes. Evidence suggests that miRNAs may play an important role in a variety of cellular biological processes, such as cell growth, differentiation, metabolism, invasion, angiogenesis. Recently, miR-21 is found to be aberrantly expressed in CRC and miR-21 has been recognized to perform significantly in CRC, where miR-21 can regulate several different target genes and pathways involving tumor proliferation, invasion and metastasis. In this study, we will focus on the critical role of miR-21 in CRC. Hopefully, the information obtained may lead to a better understanding of the pathogenesis and development of novel therapeutic strategies for this disease.