RIGI and hepatocellular carcinoma: These early studies also showed advantages of induced pluripotent stem cells (iPSCs) and human embryonic stem cells (hESCs) over hepatoma cell lines, which had classically been used for host–pathogen studies and which lack toll-like receptor 3 (TLR3) and show varying and often diminished retinoic acid inducible gene I (RIG-I) and type III interferon (IFN) responses [9,13,14,15].