The human form of OSM was originally isolated in 1986 from the growth media of PMA treated U-937 histiocytic lymphoma cells by its ability to inhibit the growth of cell lines established from melanomas and other solid tumours [REF].
The 196 residue OSM is the predominant form isolated form a variety of cell lines and corresponds to a glycoprotein of 28 KDa, although the larger 227 residue pro-OSM can be isolated from over transfected cells.