CD226 and cancer: Also, chimeric antigen receptor T cell immunotherapy (CAR-T) cell-based exosomes express CARs and contain cytotoxic molecules used for cancer therapy [31], and those released by natural killer (NK) cells express lymphocyte function-associated antigen 1 (LFA-1) and DNAX accessory molecule 1 (DNAM-1) [32], thus, mirroring the characteristic features of parent cells.