RESUMO
Objective To investigate the effect of expression of Cullin 4B (CUL4B) on the prognosis of patients after liver transplantation for hepatocellular carcinoma (HCC).Methods The retrospective case-control study was conducted.The clinicopathological data of 79 patients who underwent liver transplantation for HCC in the First Affiliated Hospital of Sun Yat-sen University between January 1,2014 and June 30,2015 were collected.The specimens of HCC tissues were collected and embedded in paraffin,and then were detected by immunohistochemistry staining.Observation indicators:(1) expression of CUL4B in HCC tissues;(2) follow-up and survival;(3) prognostic factors analysis after liver transplantation;(4) association between expression of CUL4B and recurrence and metastasis of tumor after liver transplantation.Follow-up using outpatient examination and telephone interview was performed to detect tumor recurrence or metastasis and survival up to June 2018.Measurement data with normal distribution were represented as (x)±s.The comparison between groups of count data was done using the chi-square test.The survival curve drawn using the Kaplan-Meier method,and the survival analysis was done by Log-rank test.The univariate and multivariate analysis were respectively done using the COX regression model.The association analysis was done using the Pearson test.Results (1) Expression of CUL4B in HCC tissues:immunohistochemistry staining showed that CUL4B was mainly expressed in the cytoplasm,with a powerful brownish-yellow staining.The high expression and low expression of CUL4B in HCC tissues were detected in 64 and 15 patients,respectively.(2) Follow-up and survival:79 patients were followed up for 38-56 months,with an average time of 46 months.During the follow-up,37 patients had no tumor recurrence and 42 had tumor recurrence (32 with tumor extrahepatic metastasis and 10 with intrahepatic metastasis);36 had survival and 43 died;the 1-and 3-year overall survival rates were respectively 86.84％ and 63.25％,and 1-and 3-year tumorfree survival rates were respectively 62.31％ and 51.27％.(3) Prognostic factors analysis after liver transplantation:① Results of univariate analysis showed that preoperative alpha-fetoprotein (AFP),Child-Pugh score,maximum tumour dimension,capsular invasion,intravascular tumor thrombus,Edmonson pathological grading and expression of CUL4B were related factors affecting the 3-year overall survival rate of patients after liver transplantation for HCC [Hazard Ratio (HR) =2.17,3.36,3.66,2.43,2.19,3.36,2.84,95％ confidence interval(CI):1.17-4.04,1.53-7.42,2.10-6.42,1.33-4.17,1.08-9.04,1.58-7.59,1.17-6.32,P＜ 0.05].The preoperative alpha-fetoprotein (AFP),Child-Pugh score,maximum tumour dimension,capsular invasion,intravascular tumor thrombus,Edmonson pathological grading and expression of CUL4B were related factors affecting the 3-year tumor-free survival rate of patients after liver transplantation for HCC (HR =2.06,3.72,3.16,2.36,2.83,3.21,1.69,95％CI:1.34-4.85,1.72-8.63,1.79-7.31,1.46-4.86,1.19-8.63,1.19-7.92,1.06-4.87,P＜0.05).② Results of multivariate analysis showed that maximum tumour dimension,intravascular tumor thrombus and expression of CUL4B were independent factors affecting the 3-year overall survival rate of patients after liver transplantation for HCC [Odds ratio(OR) =3.43,3.69,2.81,95％CI:1.16-6.02,1.96-9.38,1.04-9.63,P＜0.05].The maximum tumour dimension,intravascular tumor thrombus and expression of CUL4B were independent factors affecting the 3-year tumor-free survival rate of patients after liver transplantation for HCC (OR=2.25,4.72,2.74,95％C1:1.16-4.02,1.98-9.47,1.03-7.10,P＜ 0.05).The 3-year overall survival rate in patients with high-and low-expressions of CUL4B was respectively 66.7％ and 32.8％,with a statistically significant difference (x2 =5.69,P＜0.05).The 3-year tumor-free survival rate in patients with high-and low-expressions of CUL4B was respectively 73.3％ and 18.6％,with a statistically significant difference (x2 =4.63,P＜0.05).(4) Association between expression of CUL4B and recurrence and metastasis of tumor after liver transplantation:results of Pearson test showed that expression of CUL4B was significantly associated with HCC recurrence and metastasis after liver transplantation (r =0.62,P＜0.05).The further analysis showed that expression of CUL4B was significantly associated with extrahepatic metastasis after liver transplantation (r=0.84,P ＜ 0.05).Conclusion The expression of CUL4B is associated with HCC recurrence after liver transplantation,and it can be as a predictor for HCC recurrence and distant metastasis after liver transplantation.