Advancements in immunotherapy for gastric cancer: Unveiling the potential of immune checkpoint inhibitors and emerging strategies.

Gastric cancer (GC) is linked to high morbidity and mortality rates. Approximately two-thirds of GC patients are diagnosed at an advanced or metastatic stage. Conventional treatments for GC, including surgery, radiotherapy, and chemotherapy, offer limited prognostic improvement. Recently, immunotherapy has gained attention for its promising therapeutic effects in various tumors. Immunotherapy functions by activating and regulating the patient's immune cells to target and eliminate tumor cells, thereby reducing the tumor burden in the body. Among immunotherapies, immune checkpoint inhibitors (ICIs) are the most advanced. ICIs disrupt the inhibitory protein-small molecule (PD-L1, CTLA4, VISTA, TIM-3 and LAG3) interactions produced by immune cells, reactivating these cells to recognize and attack tumor cells. However, adverse reactions and resistance to ICIs hinder their further clinical and experimental development. Therefore, a comprehensive understanding of the advancements in ICIs for GC is crucial. This article discusses the latest developments in clinical trials of ICIs for GC and examines combination therapies involving ICIs (targeted therapy, chemotherapy, radiotherapy), alongside ongoing clinical trials. Additionally, the review investigates the tumor immune microenvironment and its role in non-responsiveness to ICIs, highlighting the function of tumor immune cells in ICI efficacy. Finally, the article explores the prospects and limitations of new immunotherapy-related technologies, such as tumor vaccines, nanotechnologies, and emerging therapeutic strategies, aiming to advance research into personalized and optimized immunotherapy for patients with locally advanced gastric cancer.