CCL4 and cancer: CAFs also stimulate cancer cell migration via paracrine signaling of IL-6, IL-8, insulin like growth factor-1 (IGF-1), CCL2, CCL4, CCL5, CCL22, CXCL1, CXCL2, CXCL3, CXCL5, CXCL6, TSP-1, PAI-1 osteopontin (OPN) and osteoprotegerin (OPG), all of which were shown to increase in the CM under PSC co-culture conditions (Fig. 6) [31, 32].