Immune checkpoint inhibition in NPC: A comprehensive review of PD-L1 overexpression and treatment responses

Nasopharyngeal carcinoma (NPC) is a distinct type of cancer that affects the head and neck region, and it is notably linked to infection with the Epstein-Barr Virus (EBV), particularly in endemic regions such as Southeast Asia and Southern China. Despite advances in the conventional care for NPC, including radiation and chemotherapy, the prognosis remains poor for individuals with relapsed or metastatic stages of the disease. Immune checkpoint inhibitors (ICIs), particularly those targeting the PD-1/PD-L1 axis, have emerged as an optimistic therapeutic option. PD-L1 overexpression in NPC contributes to immune avoidance and correlates in relation to these immunotherapies. This review comprehensively explores PD-L1 expression in NPC and its role in tumor immune escape, along with a detailed analysis of clinical trials investigating PD-1/PD-L1 blockade. While PD-L1 overexpression is associated with better responses to ICIs, resistance mechanisms and the complex tumor microenvironment (TME) limit their overall efficacy. We will address these barriers and highlight future directions for improving outcomes, including combination therapies, novel biomarkers, and personalized approaches to treatment. With ongoing research and clinical trials, immune checkpoint inhibition holds great potential to revolutionize NPC therapy, offering hope for improved sustained survival rates and overall well-being for individuals.