Background

Cholangiocarcinoma (CC), hepatocellular carcinoma (HCC), and pancreatic ductal adenocarcinoma (PDAC) are all devastating malignancies. Agents targeting the PD1 (programmed death 1) immune checkpoint pathway (pembrolizumab, nivolumab) have been shown to improve survival in lung, melanoma, bladder and renal cell carcinoma. Expression of the PD1 ligand (PD-L1) in tumor cells has demonstrated utility in predicting improved responses to these agents in some studies, and a PDL1 companion diagnostic has been recently FDA-approved for
NSCLC. Immune checkpoint inhibitors are actively being explored for their efficacy in various solid tumors, including hepatopancreatico-biliary (HPB) cancers. Limited data exists around PD1 and PDL1 expression in these cancers, therefore we assessed expression of PD1/PDL1 in a large cohort of patients with HPB cancers and explored the existence of accompanying genomic mutations associated with expression of PD-1/PD-L1.