Prognostic Impact of Vessels that Encapsulate Tumor Cluster (VETC) in Patients who Underwent Liver Transplantation for Hepatocellular Carcinoma

Background There is limited published information about prognostic value of vessels that encapsulate tumor cluster (VETC) based on their involvement with immune cells in hepatocellular carcinoma (HCC). Our goal was to evaluate prognostic impact of VETC in patients who underwent living-donor liver transplantation (LDLT) for HCC, focusing on the involvement of VETC with immune status in tumor microenvironment (TME). Methods Using a database of 150 patients who underwent LDLT for HCC, immunohistochemical staining of CD34 for VETC, angiopoietin-2 (Ang-2), CD3, and CD68, was reviewed with patients' clinicopathological factors. Results A strong correlation between VETC pattern and malignant potential in HCC was observed; larger tumor size (P < 0.001), more numbers of tumors (P = 0.003), higher alpha-fetoprotein levels (P = 0.001), higher des-gamma-carboxy prothrombin levels (P = 0.022), microvascular invasion (P < 0.001), and poor differentiation (P = 0.010). Overall survival (OS) of patients with VETC(+) was significantly lower than those with VETC(-) (P = 0.021; 5-year OS rates, 72.0% vs. 87.1%). Furthermore, the ratio of CD3((+)) cells was significantly lower in VETC(+) group (P = 0.001), indicating that VETC activity may be strongly correlated with lymphocyte activity. Moreover, combination status of VETC(+)/CD3(low) was an independent risk factor for mortality (hazard ratio 2.760, 95% confidence interval 1.183-6.439, P = 0.019). Additionally, the combination of VETC expression with immune status (low CD3 levels) enabled further classification of patients based on their clinical outcome. Conclusions Our results show the prognostic impact of VETC expression, tumor-infiltrating lymphocytes (TILs), and their combination in the setting of LDLT for HCC, which can be a novel prognostic biomarker for mortality after LDLT.