PDCD1 and hepatocellular carcinoma: A significant positive correlation was observed between ORAOV1 expression and levels of CTLA4, PD1, and PD-L1, as well as infiltration of tumor-promoting immune cells such as Tregs (Knochelmann et al., 2018; Noack & Miossec, 2014), MDSCs (Gomez et al., 2020; Wesolowski, Markowitz & Carson 3rd, 2013) and CAFs (Affo, Yu & Schwabe, 2017) in HCC.