Progress of immune checkpoint inhibitors in gastric cancer.

Gastric cancer (GC) is one of the most common malignant tumors globally. The screening rate of GC is low, and the early symptoms are not obvious, which affects early diagnosis, and most patients have a poor prognosis. Various treatments are available for GC, mainly surgery, chemotherapy, radiotherapy, targeted therapy and immunotherapy. Immunotherapy has made significant progress in recent years, especially for unresectable and metastatic GC. Immune checkpoints are proteins which can regulate the congenital and adaptive immunity, and are mainly expressed on immune cells. Immune checkpoints are crucial molecules that regulate the immune system, maintaining immune balance through positive or negative modulation. Tumors exploit negative immune checkpoint molecules to suppress immune responses, thereby evading immune surveillance. Immune checkpoint inhibitors (ICIs) can undo this inhibition, reactivating immune cells to destroy tumor cells. The prospects for the treatment of GC with ICIs are promising, but it also faces many difficulties and challenges. This minireview summarizes the progress of immune ICIs in GC, discusses current individualized strategies, and explores future development directions.