The Relationship between Tumor-infiltrating Lymphocytes (TILs) and Nasopharyngeal Carcinoma (NPC): A Systematic Review

INTRODUCTION: Nasopharyngeal carcinoma (NPC) is a rare and aggressive head and neck squamous cell carcinoma worldwide. Tumor-infiltrating lymphocytes (TILs) have been studied and reported to be effective targets of drugs on cancer and were related to the prognostic value. The aim of the study was to look systematically into the current literature and carefully analyze the results to explore the relationship of TILs and NPC. MATERIALS AND METHODS: Three independent reviewers conducted the literature search, searching for articles published in January 2000-January 2020 and fulfilling inclusion and exclusion criteria. The lead author independently assessed the risk of bias of each of the included studies and discussed their assessments with the other two authors to achieve consensus. Of the 1233 articles identified in database searching, 12 articles met the criteria for this review. RESULTS: The majority of the study designs were cohort (9 of 12 studies). Most of the studies discussed the prognostic significance of TILs in NPC (nine studies), two studies reported the expanded TILs for the treatment of NPC, and one study reported TILs based on one gene expression. CONCLUSION: TILs in NPC are related to the prognostic factor and development of the immunotherapy. High TILs were associated with better outcome and survival rate; and TILs have been claimed to reflect an effective anti-tumor immune response, immune response inducer, delayed tumor progression, and improving the cancer-immune microenvironment. The understanding of TILs in NPC based on gene expression becomes important information to learn more about the relationship of TILs and NPC.