GAS6 and cancer: CAFs also influence cancer cells by engaging in autocrine and paracrine signaling via secretion of multiple growth factors: TGF-β, hepatocyte growth factor (HGF), fibroblast growth factor 5 (FGF5), LIF, growth arrest-specific protein 6 (GAS6), platelet derived growth factor (PDGF), vascular endothelial growth factor A (VEGF), stromal-derived factor-1α (SDF1), osteopontin (OPN), just to mention some, as well as a myriad of cytokines, chemokines such as IL6, IL1, CXCL2, CCL20, and extracellular vesicles (i.e., exosomes) [61,67].