TGFB1 and pulmonary fibrosis: Additionally, double immunofluorescence results indicated increased STAT3 and p‐STAT3 expression in myofibroblasts from MRC‐5 cells with TGF‐β1 treatment or mice with bleomycin‐induced pulmonary fibrosis, implying the critical role of STAT3 activation in driving fibroblast‐to‐myofibroblast differentiation across experimental models (Figure 5C,D).