FAP and fibrosarcoma: As FAP is overexpressed in CAFs in the stroma of many subtypes of STS (e.g., fibrosarcoma, malignant fibrous histiocytoma, and liposarcoma) [98], in the study from Gu et al. [41] the authors investigated the role of [68Ga]Ga-DOTA-FAPI-04 in 45 patients affected by recurrent STS.