Primary tumor angiogenesis is closely related to PMN formation, as it entails the chronic release of PMN-inducing factors, such as VEGF, SDF-1, TGF-β, and TNF-α (154), that ultimately reconfigure future metastatic sites to create a permissive niche for cancer cell extravasation and proliferation. The gene discussed is CXCL12; the disease is neoplasm.