Examples of factors causing the polarization of macrophages in the tumor microenvironment are IL-4 and IL-6 [102], prostaglandin E2 (PGE2) [103], IL-10 released by Treg cells and the direct cell–cell interaction of these cells with macrophages [15,104], tumor acidification [105,106], extracellular matrix [107], granulocyte-macrophage colony-stimulating factor (GM-CSF) [108], connective tissue growth factor (CTGF) [109], and many others. The gene discussed is IL4; the disease is neoplasm.