Correlation between the expression of programmed death ligand-1 and clinicopathological factors and prognosis in hepatocellular carcinoma tissues / 中华消化杂志

ABSTRACT

Objective:To investigate the correlation between the expression of programmed death ligand-1 (PD-L1) and clinicopathological parameters and prognosis in hepatocellular carcinoma (HCC) tissues.Methods:From January 2008 to December 2016, 344 HCC patients underwent surgery in Nantong Third Hospital Affiliated to Nantong University were enrolled. The expression of PD-L1 in paraffin HCC tissues was detected by tissue microarray and immunohistochemistry. The correlation between the expression of PD-L1 in tumor cells, tumor-infiltrating immune cells and the clinicopathological parameters and prognosis of HCC patients were analyzed. And the related factors affecting the prognosis of patients were explored. Chi-square test, log-rank test and univariate and multivariate Cox regression analysis were used for statistical analysis.Results:Positive PD-L1 located in the membrane and/or cytoplasm of HCC tumor cells and tumor-infiltrating immune cells. The positive rate of PD-L1 expression in tumor cells was 21.8%(75/344). The expression of PD-L1 in tumor cells was related to histological grade and microvascular invasion, the positive rates of PD-L1 expression of patients with histological gradeⅠ, Ⅱ and Ⅲ were 7.7% (2/26), 16.5% (19/115) and 26.6% (54/203), respectively, the positive rates of PD-L1 expression of patients with or without microvascular invasion were 29.3% (34/116) and 18.0% (41/228), respectively, and the differences were statistically significant ( χ2=7.659 and 5.787, P=0.022 and 0.016). The positive expression rate of PD-L1 in tumor-infiltrating immune cells was 47.1% (162/344). The expression of PD-L1 in tumor-infiltrating immune cells was related with microvascular invasion, the positive rates of PD-L1 expression in patients with or without microvascular invasion were 56.9% (66/116) and 42.1% (96/228), respectively, and the differences were statistically significant ( χ2=6.751, P=0.009). The median survival time of patients with negative expression of PD-L1 in HCC tumor cells was 61 months (30 months, 92 months), while that of patients with positive PD-L1 expression was 16 months(6 months, 44 months), and the difference was statistically significant ( χ2=55.722, P<0.01). The expression of PD-L1 in HCC tumor cells was an independent risk factor affecting overall survival time (hazard ratio=3.090, P<0.01). Conclusions:The expression of PD-L1 in HCC tumor cells may be related to the malignancy and invasion of HCC, and may be a potential risk factor for prognosis.