PRF1 and nasopharyngeal carcinoma: As only TRIM21 was significantly associated with poor disease-free survival in NPC and its expression level was negatively correlated with the transcript levels of genes associated with CD8+ T-cell infiltration and antitumour responses, such as CD8A, PRF1, GZMA, GZMB, IFNG and LCK (Supplementary Fig. 1b, c), we selected TRIM21 for further study.