Current research on circular RNAs associated with colorectal cancer

Representing a novel type of endogenous noncoding RNAs, circular RNAs (circRNAs) have recently gained much attention for their involvement in multiple biological processes. CircRNAs are ubiquitously expressed in eukaryotic cells and modulate gene expression by acting as sponges of microRNAs (miRNAs) or other proteins, such as RNA-binding proteins (RBPs). Due to their unique structure, circRNAs are more stable than linear RNAs. Expression profiles of circRNAs are associated with clinicopathological characteristics of colorectal cancer patients, such as differentiation, TNM classification and distant metastasis. Furthermore, circRNAs play crucial roles in multiple processes associated with malignant phenotypes, including cell proliferation/cycle, apoptosis and invasion. Improvements in RNA-sequencing methods have helped researchers to elucidate molecular interactions between circRNAs and colorectal cancer. This review provides a comprehensive overview of the features and functions of circRNAs, as well as insights into their roles in the onset and development of colorectal cancer. Combined with the reported results, the identification of circRNAs associated with colorectal cancer will certainly contribute to early detection and help to design treatment strategies for colorectal cancer. Screening for circRNAs may provide an accessible, noninvasive yet highly sensitive diagnosis for colorectal cancer. Furthermore, a better understanding of the roles of circRNAs may also provide a novel predictive feature in colorectal cancer therapy and prognosis.