Recruitment and activation of quiescent tissue-resident fibroblasts into CAFs involves a variety of tumor-cell-derived activators and modulators, including TGFβ, fibroblast growth factor 2 (FGF-2), hepatocyte growth factor (HGF), PDGF, stromal-derived factor-1 (SDF-1) and signaling pathways [37] (Figure 1). This evidence concerns the gene CXCL12 and neoplasm.