Simultaneous Study of Circular RNAs and Messenger RNAs in Colorectal Cancer: The Unbalanced Fate of a Couple?

We identified 220 circular junctions, including 47 novel ones. The circRNA/mRNA ratio was 2.42-fold higher in patients compared to controls (<i>p</i> < 10^-16), irrespective of age at cancer onset. This increase was mainly driven by <i>POLD1</i> (fold change 3.84) and a single circPOLD1(3,2) with oncogenic potential Conclusions: This study supports the existence of a physiological balance between circRNA and mRNA that can be disrupted under pathological conditions. It rules out a competitive mechanism between circular and linear transcripts in CRC predisposition and raises questions about the role of specific circRNAs in the development of CRC, either as a cause or a consequence.