We are interested in circular RNAs expressed in Epstein Barr Virus (EBV)-associated diseases including Nasopharyngeal carcinoma (NPC). Circular RNAs (circRNAs) are a class of non-coding RNAs of various lengths that, unlike linear RNAs, are formed from covalently closed circles where 3’ and 5’ ends are jointed together via backsplicing event. These circRNAs are usually developmental stage and cell type-specific. Essentially, once thought to be by-product of RNA splicing or RNA-sequencing error, circRNAs are found to be biologically important for gene regulation. CircRNAs have been reported to act as miRNA sponges by serving as competitive inhibitors that suppress the ability of miRNA to bind its mRNA targets. CircRNAs are also found to interact with RNA-binding proteins (RBPs) to store, sort, or localize RBPs, and probably regulate the function of RBPs. The full spectrum of circRNA function remains to be discovered but it is a promising therapeutic target or biomarker for diseases including cancer. To date, it remains largely unknown of the pathogen and host cell circRNA gene expression profile in NPC as well as its role in the development and progression of NPC. We aim to investigate the biological role of these circRNAs expressed in NPC and its potential use for NPC diagnosis or treatment.