Document Type: Research Articles
Department of Pathology, Khon Kaen University,Khon Kaen, Thailand.
Division of Oncology, Department of Internal Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Division of Hepatobiliary Surgery, Department of Surgery, Khon Kaen University, Khon Kaen, Thailand.
Background: Effective treatments for cholangiocarcinoma (CCA) are still lacking. There are promising results of checkpoint inhibitor programmed cell death ligand-1 (PD-L1) activities in early phase trials. This study aimed to investigate the expression of PD-L1 and its relation to possible treatments for CCA. Methods: Formalin-fixed paraffin-embedded tumor samples from 46 patients with cholangiocarcinoma were retrieved. PD-L1 expression was evaluated by immunohistochemistry using anti-PD-L1 antibody, clone 5H1. A PD-L1 positive response on tumor cells was defined as >1% of tumor cell membranes stained. The association between PD-L1, clinico-pathological characteristics was analyzed using Fisher’s exact test, and survival analysis was done with the Cox regression model. Results: Out of 46 samples, 32 (70%) had positive PD-L1 expression in tumor cell membranes. The median level of PD-L1 expression was 1.75% (0-34.7). PD-L1 expression was significantly associated with stage IV disease (OR 3.98, p=0.046) and a high neutrophil/lymphocyte ratio (OR 5.36, p=0.018). PD-L1 positivity was associated with worse overall survival compared with those with a PD-L1 negative tumor but did not reach a level of significance (7.2 vs. 7.9 months, p=0.32). Conclusion: PD-L1 is widely expressed in CCA but was not predictive for overall survival. PD-L1 positivity was (7.2 and 7.9 months, p=0.32). Significantly associated with stage IV disease and a high neutrophil/lymphocyte ratio.