Collectively, these data suggest that, regardless of the specific TGF-β1 pathway activated (e.g., p53, YAP/TAZ, PI3K/AKT), PAI-1 regulates myofibroblast differentiation both in vitro and in vivo and may well do so in the CCA TME. The gene discussed is TGFB1; the disease is cholangiocarcinoma.