Abstract 3981: The GZMK CD8 T cells cluster defined by single-cell transcriptome profiling with innate-like functions is a predictor of survival in hepatocellular carcinoma patients

Abstract Hepatocellular carcinoma (HCC), the sixth most common cancer globally in 2020, is closely associated with hepatitis B or C infections and non-alcoholic steatohepatitis (NASH). Despite advancements in surgical and systemic therapies for early and advanced stages, tumor relapse and poor prognosis remain significant challenges, necessitating improved therapeutic approaches. This study highlights the role of GZMK-expressing CD8+ T cells in HCC, identified through single-cell transcriptome profiling. These cells exhibit transcriptional profiles similar to hepatotoxic CD8+ T cells in chronic hepatitis B and innate-like CD8+ T cells in chronic hepatitis C. GZMK CD8+ T cells are enriched with tissue-resident memory traits and are detectable in peripheral blood and tumor tissues. Furthermore, within the tumor microenvironment, GZMK CD8 cells expressed surface receptors resembling those of NK cells, allowing them to release IFN-γ and exert non-antigen specific innate-like cytotoxic effects. These GZMK CD8+ T cells could be identified as CD38+HLA-DR+ CD8+ T cells by flow cytometry. These CD38+HLA-DR+ CD8+ T cells increased in the peripheral blood of HCC patients and accumulated in tumor tissue. Cytokines such as IL-12, IL-15, and IL-18 were shown to stimulate the proliferation of CD38+HLA-DR+ CD8+ T cells, enhancing their production of IFN-γ and granzyme B, as well as their expression of NK-like receptors and effector molecules. These bystander-activated CD38+HLA-DR+ CD8+ T cells, derived from effector memory (EM) and effector memory RA (EMRA) subsets, displayed cytotoxicity against K562 and THP-1 cell lines through DNAM-1, granzyme B, and perforin. A high GZMK CD8+ T cell signature was strongly associated with improved overall survival (OS) and progression-free survival (PFS) in the TCGA-HCC database. These findings suggest that GZMK CD8+ T cells have a significant impact on survival in HCC, possibly through their innate-like cytotoxic functions. This unique subset may serve as a biomarker and a potential therapeutic target in HCC management. Citation Format: Wei-Ting Ku, Chien-Hao Huang, Jian-He Fan, Cheng-Heng Wu, Tsung-Han Wu, Wei Teng, Po-Ting Lin, Chung-Wei Su, Yung-Chang Lin, Chun-Yen Lin. The GZMK CD8 T cells cluster defined by single-cell transcriptome profiling with innate-like functions is a predictor of survival in hepatocellular carcinoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3981.