OX40 expression in hepatocellular carcinoma is associated with a distinct immune microenvironment, specific mutation signature, and poor prognosis

ABSTRACTImmunotherapy's effect against hepatocellular carcinoma (HCC) is hampered by immunosuppressive mechanisms in the tumor microenvironment. We assessed the clinicopathologic and biologic relevance of OX40, a costimulatory molecular expressed by regulatory T cells (Tregs), in HCC. We analyzed the immunohistochemistry data of 316 patients treated at West China Hospital (WCH) and the RNA sequencing data of 370 patients in The Cancer Genome Atlas (TCGA) to determine the clinicopathologic significance of OX40 in HCC. We also assessed associations between OX40 and multiple immune-related markers. Using the TCGA data, we further characterized the transcriptome, immune cell functions, and mutation signature related to OX40. We found that OX40 expression was higher in HCC than in adjacent liver tissue. In the WCH set, 136 (43%) patients had high-OX40 expression, whereas in the TCGA set, 247 (67%) patients had high-OX40 expression as determined by the X-tile program. High-OX40 expression was associated with hi...