TRIM21 and nasopharyngeal carcinoma: In addition, IFI16 is reported as a TRIM21 downstream and DNA sensor to activate STING-dependent type-I IFN signalling24, we thus investigated the interaction between TRIM21 and IFI16 in NPC cells, and surprisingly found that TRIM21 did not interact with IFI16 (Supplementary Fig. 2d).