miRNA biomarkers for NPC diagnosis and prognosis

MicroRNAs (miRNAs) are short non-coding RNAs that have been termed “master regulators of the genome” given their significance in post-transcriptional gene regulation, and roles in a multitude of normal and disease processes. In cancer, dysregulation of miRNAs can facilitate disease progression and therapeutic resistance, affecting tumour-suppressors and oncogenes. Nasopharyngeal carcinoma (NPC) is a unique head and neck cancer that is frequently associated with the Epstein-Barr virus (EBV). Advances in miRNA profiling techniques have highlighted the significance of both EBVand human genome-encoded miRNAs in the pathogenesis of NPC. These miRNAs have been implicated in critical NPC processes such as epithelial-to-mesenchymal transition (EMT) and metastasis, while further promoting chemoresistance and radioresistance. MiRNA signatures derived from profiling data and bioinformatics/statistical analyses may be particularly useful for the diagnosis of NPC, as well as the stratification of patients into clinically relevant groups to guide treatment selection. The identification and characterization of biologically relevant biomarkers will be crucial to improving patient outcomes and achieving greater understanding of the molecular underpinnings of NPC. This review integrates the literature on EBV-miRNAs, cellular miRNAs, and miRNA signatures to guide future research, while acknowledging challenges in the selection and clinical implementation of relevant miRNA biomarkers and signatures.