TCF21 and cystic fibrosis: Two markers which appear to be relatively more specific to CF are the platelet‐derived growth factor receptor α (PDGFRα) and the transcription factor Tcf21, both of which are expressed in the majority of myofibroblast‐forming cells (Smith et al, 2011; Acharya et al, 2012; Pinto et al, 2016).