Circular RNAs (circRNAs) and Linear Long Non-Coding RNAs (lncNAs) in Solid Tumors: Their Multifaceted Functional Role and Emerging Potential as Molecular Cancer Biomarkers

Circular RNAs (circRNAs) are a neglected RNA type deriving from the back-splicing of primary transcripts. The vast majority of them are considered to be non-coding, thus resembling linear long non-coding RNAs (lncRNAs). Moreover, their functions are similar to those of linear lncRNAs. Multiple lines of evidence increasingly link mutations and dysregulation of circRNAs and linear lncRNAs to diverse human diseases, including cancer and leukemia. Both these types of RNA have been shown to interact with other RNA molecules including miRNAs, DNA and/or chromatin, as well as with proteins. Moreover, representatives from these two groups of molecules have been suggested as ideal molecular cancer biomarkers, so far.

This Research Topic aims to present new aspects regarding the biological role and diverse functions of circRNAs and linear lncRNAs in human malignancies. Another goal of this Research Topic is to highlight new signaling axes involving circRNAs or linear lncRNAs and miRNAs, thus indirectly leading to regulation of protein-coding gene expression and modulations of signaling pathways. Newly described interactions between circRNAs or linear lncRNAs and RNA-binding proteins could also emerge, thus deepening our understanding about the biological impact and role of these interactions. Expression of particular non-coding RNAs has been associated with several aspects of cancer cell life, including proliferation and migration. Current knowledge supports the further investigation of circRNAs and linear lncRNAs in the field of cancer pathobiology. Moreover, this Research Topic aims to highlight the potential of circRNAs and linear lncRNAs as candidate tumor biomarkers with unique features, including high diagnostic, prognostic, and/or therapy response-predictive or efficacy-monitoring potential. It should be noted that the high stability of such molecules in human bodily fluids render both these types of RNA particularly attractive for molecular oncologists.

This Research Topic will focus on the role of circRNAs and linear lncRNAs in cancer, covering molecular, cellular and (pre)clinical aspects, aiming to elucidate the implication of these types of RNA in human malignancies. Moreover, research highlighting the potential and clinical value of circRNAs and linear lncRNAs as candidate tumor biomarkers, either in solid tumors or in blood serum / plasma, fits also within the scope of this Research Topic. The authors are encouraged to submit their original research studies concerning this field of cancer biology. Reviews that highlight new findings in the above areas are also welcome.

Please note: manuscripts consisting solely of bioinformatics or computational analysis of public genomic or transcriptomic databases which are not accompanied by validation (independent cohort or biological validation in vitro or in vivo) are out of scope for this section and will not be accepted as part of this Research Topic.