 the M2 macrophages are a type of immune cell that has been found to have a wide range of functions in the body. They are characterized by the expression of certain genetic markers such as those for scavenger receptors, enzymes, growth factors, hormones, cytokines, and cytokine receptors. These markers are thought to provide insight into the differentiation of the M2 macrophages from other types of macrophages. Additionally, the M2 macrophages are influenced by the tissue environment and a neuroendocrine system, which may help explain why they have such varied functions. Finally, the evolutionary origins of the M2 macrophages are discussed. This article was authored by Thomas Risser.