TGFB1 and osteosarcoma: Mazumdar et al. demonstrated that exosomes derived from osteosarcoma cells can induce lung fibroblast reprogramming and thereby direct fibroblast activation and differentiation toward a myofibroblast/cancer-associated stromal fibroblasts (CAFs) phenotype through exosome-associated TGFβ1 and SMAD2 pathway activation.