CXCL12 and cancer: Tumor-associated macrophages secrete different cytokines, such as IL-6, IL-10 and TNF-α, chemokines CCL17, CCL22, CCL24, CXCL12, CXCL8 and growth factors TGF-β, vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), fibroblast growth factor (FGF), along with other soluble factors, such as osteopontin, cyclooxygenase-2, and matrix metalloproteinase (MMPs), modulating tissue architecture and favoring tumor cell migration, invasion, cancer progression, and metastasis [56,57,58].