Abstract A123: Infiltration of CD69- T cells in tumor tissue reflects longer recurrence-free survival in surgically resected hepatocellular carcinoma

Abstract Background: Tumor-infiltrating T cells in hepatocellular carcinoma (HCC) are heterogeneous, which can be separated into the CD69+ tissue-resident T cell population and the CD69- circulating T cell population. However, the impact of these distinct T cell populations on patient prognosis remains controversial and further studies are needed. Method: We collected HCC (tumor) and farthest liver tissues (non-tumor) obtained during hepatectomy in 57 HCC patients with various etiologies of chronic liver disease. The patient cohort included the following etiologies: hepatitis B virus (HBV, 49%), alcohol-related liver disease (16%), HBV combined with alcohol-related liver disease (HBV+Alc, 21%), and unknown etiology (14%). Single-cell dissociation and flow cytometry were performed to assess the expression of CD69+ and CD69- T cells, and the correlation between these populations and recurrence-free survival (RFS) was evaluated. Result: The expression levels of CD69+/CD69- subpopulations within CD4+ and CD8+ T cells in both non-tumor and tumor tissues exhibited patient-specific variability. These populations exhibited different phenotypes depending on alcohol etiology. The frequency of the CD69- population was lower in both non-tumor and tumor tissues, while the CD69+CD103+ and CD69+CD103- subpopulations were significantly increased in patients with alcohol etiology compared to those with non-alcohol etiology (p<0.05). In tumor tissues, the mean fluorescence intensity (MFI) of PD-1 was significantly lower in CD69- cells compared to CD69+ cells across both CD4 and CD8 T cell populations (p<0.05), suggesting that CD69- cells may possess a less exhausted phenotype. Additionally, we observed in further analysis of tumor tissues that the MFI of PD-1 in the CD69- population of both CD4+ and CD8+ T cells was higher in patients with alcohol etiology compared to those with non-alcohol etiology. This result suggests that CD69- T cells, which have anti-tumor immune functions, may undergo exhaustion due to alcohol exposure. Importantly, higher frequencies of CD69- T cells in tumor tissues correlated with decreased recurrence risk, suggesting a potential protective role against HCC recurrence. Conclusion: We have identified distinct roles for tumor-infiltrating T cells in HCC tissues. CD69+ population is associated with immune exhaustion, which might be related to tumor aggressiveness. In contrast, the CD69- population among tumor-infiltrating T cells appears to play a crucial role within the tumor microenvironment, potentially related to liver inflammation and alcohol intake. Further studies are needed to elucidate the functional differences between these populations. Citation Format: Eun Ji Jang, Min Gu Kim, Pil Soo Sung. Infiltration of CD69- T cells in tumor tissue reflects longer recurrence-free survival in surgically resected hepatocellular carcinoma [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A123.