Cancer Immunotherapy: From Immune Surveillance to Clinical Applications

Cancer immunotherapy is an important means of treating cancer by clearing malignant cells through the immune system. Unlike chemotherapy or radiation therapy that directly targets tumors, immunotherapy enhances immune recognition and memory, thus having higher specificity and the possibility of lasting remission. The immune surveillance theory provided the foundation for this method, which was later refined into an immune editing model. Tumors utilize these processes through immune checkpoint signaling, inhibitory cell recruitment, metabolic competition, and the formation of an immunosuppressive microenvironment, which presents significant challenges for treatment. The advancement of medical technology has not only driven the development of immune checkpoint inhibitors (ICIs), but also demonstrated their significant efficacy - drugs such as anti-CTLA-4 and anti-PD-1/PD-L1 antibodies have produced meaningful results in melanoma, lung cancer, and other cancers. Significant progress has been made in cell therapy for hematological cancers, with tumor infiltrating lymphocytes (TIL) and chimeric antigen receptor (CAR) T cells demonstrating considerable effectiveness. Cancer vaccines are used to induce targeted adaptive responses. Immune modulators can enhance innate immune activation and strengthen checkpoint blockade.