CXCL8 and neoplasm: Apart for their “canonical role”, MCs have been reported to be able to produce several factors that can support tumor growth, such as CXCL8/IL-8, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), stem-cell factor (SCF), together with matrix metalloproteases (MMPs), necessary for the ECM remodeling, thus favoring metastasis [94–96].