ISG15 and hepatocellular carcinoma: In patients of early HCC stage (stage I/II), the overall survival rates were obviously lower in patients with higher‐than‐average ISG15 levels (p = 0.0064, Figure S1B, Supporting Information, data from cBioPortal database); whereas in patients with advanced HCC stage (stage III/IV), the difference was not significant (p = 0.15, Figure S1B, Supporting Information).