M2 macrophages, termed tumor associated macrophages (TAMs), play a pivotal role during the proliferation, invasion, and metastases of tumor cells via expressing soluble proteins and cytokines, such as IL-10, matrix metalloproteinases (MMPs), urokinase-type plasminogen activator (uPA), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), granulocyte-macrophage colony stimulating factor (GM-CSF), and migration stimulating factor (MSF) [31, 32]. The gene discussed is CSF2; the disease is neoplasm.