Furthermore, in patients with HBV-related HCC, upregulation of circulating PD-1/PD-L1 is associated with poor post-cryoablation prognosis [26] and PD-1+ tumour-infiltrating lymphocytes is correlated with portal vein thrombosis and may serve as a potential prognostic marker [27]. This evidence concerns the gene PDCD1 and Portal vein thrombosis.