Objective To investigate the expression of human leukocyte antigen-G （HLA-G） in hepatocellular carcinoma （HCC） tissues， and to evaluate the prognosis of patients after liver transplantation. Methods The clinical data of 83 patients with HCC who underwent liver transplantation from January 2004 to May 2008 in the Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University were analyzed retrospectively. The expression of HLA-G in HCC tissues was detected by using immunohistochemical analysis. The Kaplan-Meier method was used to evaluate the cumulative survival rate and tumor-free survival rate. Log-rank test and Cox regression model were used to analyze the single and muti-factor for tumor-free survival rate, respectively. Results Among the 83 patients，there were tumor recurrence in 35 patients （42.2%）. The 1-year，3-year, and 5-year of cumulative survival rate was 97.2%，89.8%, and 43.1%, respectively. The 1-year，3-year， and 5-year of tumor-free survival rate was 93.6%，68.9%, and 38.7%, respectively. The positive rate （68.7%） of HLA-G expression in HCC tissues was significantly higher than that in paracancerous tissues （15.7%）, P＜0.01. A significant association was found between expression of HLA-G and tumor size， vascular invasion, and pathology differentiation （P＜0.05）. Single factor analysis showed that the expression of HLA-G （P＜0.01）， tumor size （P＜0.05）， vascular invasion （P＜0.01）， and pathology differentiation （P＜0.01） effected on tumor-free survival rates of HCC patients after liver transplantation. The tumor-free survival rate in positive expression of HLA-G group was significantly lower than that in negative expression of HLA-G group （P＜0.01）. Cox regression model analysis showed that the expression of HLA-G （P＜0.05）， vascular invasion （P＜0.01）， and pathology differentiation （P＜0.05） were independent risk factors that affected the tumor-free survival rate of HCC patients after liver transplantation. Conclusions There is expression of HLA-G in HCC tissues. The independent risk factors that affecting the tumor-free survival rate of HCC patients after liver transplantation include the expression of HLA-G， vascular invasion, and pathological differentiation. Taking interferential measures for patients with positive expression of HLA-G and strict selection of indication of liver transplantation for HCC can reduce the recurrence rate of tumor.
Objective To construct the expression vector of HLA-G-shRNA and investigate the effect of HLA-GshRNA from NK cell lysis. Methods Four HLA-G shRNA plasmids were constructed and transiently transfected to Bel-7402 cell lines， the levels of mRNA and protein of HLA-G were detected by Real-Time PCR and Western blot. The cytotoxicity of NK-92MI cells against the transfected cells was analyzed by LDH releasing assay. Results The gel electrophoresis and sequencing showed that the inserted sequence was identical to the one which we designed, and no aberrations such as mutation，deletion or insertion occurred. The expressions of HLA-G confirmed by Real Time-PCR and Western blot were significantly down-regulated. Bel-7402 cell lines transfected HLA-G shRNA showed higher lytic activity （P＜0.01）. After KIR2DL4 receptor blocked，lytic activity of NK-92 MI cell were decreased （P＜0.01）. Conclusions HLA-G shRNA plasmids are successfully constructed and HLA-G down-regulated can increase NK cytolysis against Bel-7402 cell. After HLA-G combines with KIR2DL4 receptor at the surface of NK cells， the inhibition effect is transferred.