VTCN1 and hepatocellular carcinoma: Aberrant B7S1 expression has been reported in a vast majority of human malignancies, including melanoma (Quandt et al., 2011), renal cell carcinoma (Krambeck et al., 2006), breast cancer (Tringler et al., 2005), non-small cell lung cancer (Sun et al., 2006), thyroid cancer (Zhu et al., 2013), and hepatocellular carcinoma (Kang et al., 2017).