FAP and neoplasm: In this regard, more subsequent in-depth studies [97] further distinguished two subgroups of PDAC with an activated stroma profile: tumors with an ACTA2-dominant fibroblast-rich stroma (30% of PDAC) and PDAC neoplasms with an FAP-dominant fibroblast-rich stroma (44%), depending on the pattern of expression of the CAF activation markers ACTA2 (also known as α-SMA) and FAP, respectively [35,53,97].