al., Epstein–Barr virus-encoded RNA 1 (EBER1) delivered to EBV-infected cancer cells in the form of MDM-derived exosomes have been determined to upregulate IDO1 through IL-6 and TNF-α via retinoic acid-inducible gene-I (RIG-I) and the subsequent NF-κB and p38 MAPK pathway in EBV-infected cancer cells [83]. Here, IL6 is linked to cancer.