Fig. 1

The potential origins and generation of MAFs. Possible progenitors of metastasis-associated fibroblasts (MAFs) are resident fibroblasts, hepatic stellate cells, mesothelial cells, mesenchymal stem cells and stromal cells derived from primary tumors or other sites. After receiving the stimuli from tumor cells or other cells, MAFs are activated. CAF, cancer-associated fibroblast; NETs, neutrophil extracellular traps; TGF-β, transforming growth factor-β; PDGFs, platelet-derived growth factors