FAP and pulmonary fibrosis: FAP is also found to be highly expressed in the collagen-accumulated loci of several fibrotic diseases including keloid (Dienus et al., 2010), liver fibrosis (Levy et al., 2002), myocardial infarction (Tillmanns et al., 2015), lung fibrosis (Acharya et al., 2006), Crohn’s disease (Truffi et al., 2018), and arthritis (Croft et al., 2019).