AB025. S5A-1. Immune biomarkers of cholangiocarcinoma: microsatellite instability and EBV

Abstract: Cancer immunotherapy is becoming a more often-used strategy among therapeutic options over the past years and has a proven track record against several types of malignancies. However, the efficacy of immune therapy in cholangiocarcinoma (CCA) is still unclear. Recently, two clinical trials, keynote028 and keynote158, revealed the objective response rate of immune checkpoint inhibitor in CCA was 5.8–17%. These less-than-stellar results imply an urgency to identify predictive immune biomarkers for CCA. In this talk, we are going to discuss two potential immune biomarkers: microsatellite instability (MSI) and Epstein-Barr virus (EBV) infection. MSI is due to a deficiency in DNA mismatch repair that leads to accumulation of insertions and deletions in DNA repeat sequences, and thereby stimulate immune surveillance. EBV-associated CCA is a rare subgroup of intrahepatic CCA and demonstrates unique clinical features, including infiltration with lymphocytes in tumor, which may enhance immune response.

Keywords: Immune biomarkers; MSI and EBV-related CCA