Oncostatin M (OSM) is a multifunctional cytokine, and belongs to Interleukin-6 (IL-6) subfamily, which also includes IL-11, leukemia inhibitory factor (LIF), ciliary neurotropic factor, cardiotrophin-1, and novel neurotropin-1. ED50 < 10.0 ng/ml, measured by a cell proliferation assay using TF-1 cells, corresponding to a specific activity of > 1.0 × 105 units/mg.