Tissue microarray (TMA, Shanghai Outdo Biotech Company) containing 297 pairs of HCC tumors from patients who underwent curative resection was used in this study. We obtained approval for this retrospective study from the ethical committee of Qilu Hospital, Shandong University. Curative resection was defined as complete macroscopic removal of the tumor without exposure of tumor cells on the cut surface with macroscopic tumor clearance confirmed on a computed tomography (CT) scan or magnetic resonance imaging (MRI) study of the liver 1 month after hepatic resection 26 (link). Tumor staging was determined according to the TNM classification system of the 8th edition. The histological grade of tumor differentiation was assigned by the Edmondson grading system.
The TMA sections were used for immunochemistry staining. Monoclonal antibodies against human MMP2 (1:100), MMP9 (1:100), RECK (1:100) were purchased from DakoCytomation, Denmark. Immunohistochemistry was carried out using a two-step protocol (Novolink Polymer Detection System, Novocastra, Newcastle, UK) as previously described 27 (link). Monoclonal antibodies against human PD-L1 (1:100) was purchased from Abcam, Cambridge, UK.
The TMA sections were used for immunochemistry staining. Monoclonal antibodies against human MMP2 (1:100), MMP9 (1:100), RECK (1:100) were purchased from DakoCytomation, Denmark. Immunohistochemistry was carried out using a two-step protocol (Novolink Polymer Detection System, Novocastra, Newcastle, UK) as previously described 27 (link). Monoclonal antibodies against human PD-L1 (1:100) was purchased from Abcam, Cambridge, UK.
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