CAR-T Immunotherapy to Beat Solid Tumors: From Challenges to Improvements

Chimeric antigen receptor T (CAR-T) cell immunotherapy shows potential and guarantee for clinical application in solid tumor treatment, although a section of difficulties must be overcome. Compared with conventional antitumor therapies, the advantages of CAR-T cell treatment include high specificity, great killing power, and long-term effectiveness. But various difficulties in treating solid tumors by CAR-T immunotherapy include intracellular signaling of CARs, immune escape due to antigenic heterogeneity of malignant tumors, physical or cytokine barriers that prevent CAR-T cell entry or limit their persistence, tumor microenvironment of other immunosuppressive molecules, and side effects. This paper describes CAR-T immunotherapy's mechanisms, development, and applications and discusses the status, difficulties, solutions, and future directions of treating solid tumors by CAR-T immunotherapy.