Functional mechanisms of circular RNA‑encoded peptides and future research strategies and directions in nasopharyngeal carcinoma (Review).

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy closely associated with Epstein‑Barr virus (EBV) infection. Although patients with early‑stage NPC can achieve a high cure rate through radiotherapy, recurrence and distant metastasis remain the primary causes of treatment failure in patients with advanced‑stage NPC. Circular RNA (circRNA) is a class of covalently closed non‑coding RNAs involved in multiple aspects of tumor biology. Recent evidence has shown that certain circRNAs can encode functional peptides, which participate in the regulation of tumor‑related signaling pathways. In NPC, circRNAs have been implicated in the modulation of signaling pathways, including NF‑κB and JAK/STAT, both of which are activated in the EBV‑infected microenvironment. Furthermore, frequently mutated genes in NPC, such as TNF receptor‑associated factor 3 and cylindromatosis lysine 63 deubiquitinase, are known regulators of the NF‑κB pathway, suggesting a potential link between genetic alterations and circRNA‑related mechanisms. This article systematically reviews the biological mechanisms of circRNA‑encoded peptides, summarizes the expression and function of circRNA in NPC and focuses on discussing the potential roles of circRNA‑encoded peptides in tumor microenvironment regulation, immune escape and clinical application prospects. By integrating existing research results, this article aims to provide a new perspective and theoretical basis for the in‑depth exploration of circRNA‑encoded peptides in the field of NPC.