Chimeric antigen receptor T (CAR-T) cell immunotherapy for sarcomas: From mechanisms to potential clinical applications.

Survival rates for sarcoma patients have plateaued in the past few decades and remain especially grim for those with recurrent or metastatic disease. This has prompted investigation into novel immunotherapies for sarcomas, especially after their recent and well-recognized successes in other cancers. One such modality, the Chimeric Antigen Receptor (CAR) T Cell therapy, has shown promising results in treating B-cell lymphoma and acute lymphoblastic leukemia. This novel therapy functions by fusing a specific antibody derived single-chain variable fragment (scFv) with a T-cell which recognizes a specific tumor-associated antigen (TAA). Several sarcoma-associated antigens (SAA) amenable to CAR-T cell treatment have recently emerged with encouraging results. These include human epidermal growth factor receptor 2 (HER2), disialoganglioside (GD2), interleukin 11 Receptor Subunit Alpha (IL-11RA), fibroblast activation protein (FAP), B7-H3, CD44v6, insulin-like growth factor 1 receptor (IGF-1R), and tyrosine kinase orphan-like receptor 1 (ROR1). Given the limitations of current medical therapies, novel treatment strategies are urgently needed. As a sarcoma treatment modality, CAR-T cell therapy is highly promising and continues to draw interest especially as new clinical trials emerge. Here we review recent breakthrough CAR-T cell studies in sarcoma, the targets which define them, and approaches to minimizing host cytotoxicity.