RIGI and nasopharyngeal carcinoma: It has been shown that circBART2.2, which is highly expressed in NPC, can activate the transcription factors interferon regulatory Factor 3 (IRF3) and nuclear factor kappa-B (NF-κB) upon binding to the decapping enzyme region of retinoic acid inducible gene protein I (RIG-I), which promotes the transcription of PD-L1 and thus leads to tumor immune escape (122) (Figure 2 and Table 1).