Tumor angiogenic mechanisms can be triggered also by proinflammatory cytokines (such as IL-8) [57], chemokines such as CXC motif chemokine ligand 1 (CXCL1) [58], or thrombospondin-1 (TSP-1) and TSP-2 [59] via sonic hedgehog (Shh) signaling. This evidence concerns the gene THBS1 and neoplasm.