CFTR and cystic fibrosis: It should be considered that besides the altered CFTR-TWIST1 axis, that incites a first hit, other pathological conditions found in CF airways may advance CF cells towards the partial EMT condition, such as chronic inflammation, i.e., increased TGF-β1 [121], epithelial remodeling, pathogen invasion [15], hypoxia and aberrant myofibroblast persistence [129] (Figure 5).