CARS1 and neoplasm: To precisely target antigens expressed on tumors without damaging normal tissue cells, endogenous tumor-infiltrating lymphocytes (TILs) can be obtained and expanded from autologous tumor resection specimens or biopsies, or peripheral blood T cells can be genetically engineered in vitro with antitumor T cell receptors (TCRs) or chimeric antigen receptors (CARs) (Rosenberg and Restifo, 2015).