GDF-15 belongs to the TGF-β cytokine family, whose members play an important role during prenatal development and postnatal growth, and the remodeling and maintenance of a variety of tissues and organs. GDF-15 is expressed predominantly in the placenta and, to a much lesser extent, in various other tissues. The presence of GDF-15 in amniotic fluid and its elevated levels in the sera of pregnant women suggest GDF-15's involvement in gestation and embryonic development. GDF-15 generally exerts tumor suppressive activities and is one of the predominant factors produced and secreted in response to activation of the p53 pathway. Interestingly, the serum level of GDF-15 is positively correlated with neoplastic progression of several tumor types, including certain colorectal, pancreatic, and prostate cancers. Recombinant Human GDF-15/MIC-1 is a disulfide linked homodimeric protein consisting of two 112 amino acid polypeptide chains. The calculated molecular weight of Recombinant Human GDF-15/MIC-1 is 24.6 kDa.