S100A2, also known as CaN19 or S100L was first isolated from bovine lung tissue. However, in human tissue it was discovered several years later, in the mammary epithelial cells.Under normal circumstances it is highly expressed in human lungs, prostate, kidneys, hair follicles and salivary and mammary glands. S100A2 is predominantly found in the nucleus, which is not very common in other S100 proteins. Moreover, it can also be found in the cytoplasm, and its distribution is rather diffuse. Its occurrence in cytoplasm is most likely dependent on calcium levels in the cell. In the extracellular environment, it can be found as a homodimer in vivo and in vitro, but it also exists in monomeric, polymeric and multimeric forms. In multimeric form, it functions as a RAGE receptor ligand.