Abstract 5355: A novel subset of Treg-like MDSCs expressing LAG-3 found in advanced gastric cancer

Abstract

Abstract The development and progression of cancers are frequently promoted by immunosuppressive cells, such as Treg and myeloid-derived suppressor cells (MDSCs) mediated by various immune checkpoint molecules. Therefore, MDSCs are potential diagnostic and therapeutic targets in cancer. However, the definitive cell surface markers for defining MDSC and the subset that correlates with cancer progression are not clear. In our previous studies, there was no difference in the amount of total granulocyte MDSCs (G-MDSCs) between early and advanced gastric cancer. We inferred that there is a novel subset of G-MDSCs involved in cancer progression rather than the previous marker-based classification. The purpose of this study is to analyze MDSCs in gastric cancer patients at different stages of progression and to identify subsets of G-MDSCs that are involved in cancer progression. As a result, we identified a subset of novel G-MDSCs that correlate with cancer progression by expressing LAG-3. LAG-3 is a molecule that is expressed in Tregs and causes strong immunosuppression, suggesting that it is involved in the immunosuppressive potential of MDSCs. Citation Format: Takumi Iwasawa, Suguru Yamauchi, Tetsu Fukunaga, Hajime Orita, Tomoaki Ito, Kato Kazunori. A novel subset of Treg-like MDSCs expressing LAG-3 found in advanced gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5355.