For example, fibroblast activation protein-α (FAP)-expressing exosomes, serving as tumor vaccine, could induce strong and specific cytotoxic T lymphocyte (CTL) immune responses against tumor cells and FAP+ cancer-associated fibroblasts (CAFs).51 Consequently, these exosome-based tumor vaccines reshaped immunosuppressive TME in colorectal cancer (CRC), melanoma, lung cancer, and breast cancer. The gene discussed is FAP; the disease is breast cancer.