We next investigated the mechanism by which VDAC2 affects the release and accumulation of cytosolic mtDNA in NPC cells during IR treatment and revealed that knockout of VDAC2 significantly decreased the abundance of cytosolic mtDNA fragments in irradiated TRIM21-WT and TRIM21-KO NPC cells (Fig. 4a). This evidence concerns the gene TRIM21 and nasopharyngeal carcinoma.