Numerous studies found that TGF-β1 can induce the transformation of fibroblasts into myofibroblasts by promoting the expression of Smad3 and p38MAPK, can stimulate the mitosis and synthesis and deposition of pulmonary fibroblasts, and induce the occurrence of pulmonary fibrosis [22,23]. The gene discussed is TGFB1; the disease is pulmonary fibrosis.