Myeloid-derived suppressor cells modulation in the context of tumor microenvironment for gastric cancer.

Gastric cancer (GC) exhibits aggressive behavior and high mortality rates globally. In this respect, the effectiveness of chemotherapy and immunotherapy is hindered by various factors including tumor heterogeneity, immune phenotypes, chronic H. pylori infection, and an immunosuppressive tumor microenvironment (TME). The immunosuppressive TME is fostered by multiple immune cell subpopulations as tumor-associated neutrophils, tumor-associated macrophages, tumor-associated dendritic cells, regulatory T cells, and myeloid-derived suppressor cells (MDSCs). The MDSC abundantly infiltrates gastric TME, which interacts with H. pylori infection and is influenced by reactive oxygen species (ROS), chronic inflammation, and hypoxia. Understanding its cellular and molecular biology of GC is crucial for developing novel therapeutic options. Current preclinical evidence is emerging to support translational oncology on MDSC immunotherapy. This article review suggests MDSC modulation may be a promising avenue for enhancing chemotherapy and immunotherapy responses against GC.