The circ RNA –micro RNA code: emerging implications for cancer diagnosis and treatment

Circular RNA s (circ RNA s) comprise an emerging new class of endogenous RNA s expressed abundantly by the eukaryotic transcriptome. They are characterized by a covalently closed loop structure, resulting in RNA molecules that are more stable than linear RNA s. A growing number of studies indicate that circ RNA s play critical roles in human diseases and show great potential as biomarkers and therapeutic targets. The molecular events determined by circ RNA activity, the circ RNA code, involve other types of noncoding RNA molecules, primarily micro RNA s, long noncoding RNA s, and RNA ‐binding proteins. Herein, we mainly focus on the circ RNA –micro RNA code, showing how this relationship impacts the regulation of gene expression in cancer. The emerging roles for circ RNA s in oncogenic pathways highlight new perspectives for the detailed molecular dissection of cancer pathogenesis and, at the same time, offer new opportunities to design innovative therapeutic strategies. Here, we review recent research advancements in understanding the biogenesis, molecular functions, and significance of circ RNA s in cancer diagnosis and treatment.