FAP and glioblastoma: Although a few preclinical studies have assessed the possibility of FAP as a therapeutic target in GBM, the design of FAP-targeted therapy in GBM is still lacking, and the main challenges for FAP-targeted therapy are the high heterogeneity of GBM, the effects of GBM cells on distant tumor-adjacent brain tissues to express FAP and the expression of FAP in other reactive conditions including fibrosis and inflammation.