Abstract 767: TCR sequencing can identify and track tumor-specific T cell populations and is a predictive biomarker of response to DC vaccination in glioblastoma patients

Abstract

Abstract While immunotherapeutic strategies are emerging adjunctive treatments for cancer, sensitive methods of monitoring the immune response after treatment remain to be established. We used a novel next generation sequencing (NGS) approach to determine whether quantitative assessments of tumor infiltrating lymphocyte (TIL) content and the degree of overlap of T cell receptor (TCR) sequences in brain tumors and peripheral blood were predictors of immune response and overall survival in glioblastoma (GBM) patients treated with autologous tumor lysate-pulsed dendritic cell (DC) immunotherapy. A significant correlation was found between a higher estimated TIL content and increased time to progression (TTP) and overall survival (OS). In addition, we were able to assess the proportion of shared TCR sequences between tumor and peripheral blood at time points before and after therapy, and found the level of TCR overlap to correlate with survival outcomes. Higher degrees of overlap, or the development of an increased overlap following immunotherapy, correlated with improved clinical outcome, and may provide insights into the successful, antigen-specific immune response. Citation Format: Shaina Sedighim, Melody Hsu, Tina Wang, Richard G. Everson, Alex Tucker, Joseph P. Antonios, Lin Du, Ryan Emerson, Erik Yusko, Catherine Sanders, Harlan Robins, William Yong, Tom B. Davidson, Gang Li, Linda M. Liau, Robert Prins. TCR sequencing can identify and track tumor-specific T cell populations and is a predictive biomarker of response to DC vaccination in glioblastoma patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 767.