Growth/differentiation factor 15 is a protein that in humans is encoded by the GDF15 gene. GDF15 was first identified as Macrophage inhibitory cytokine-1 or MIC-1. It is a protein belonging to the transforming growth factor beta superfamily. Under normal conditions, GDF15 is expressed in low concentrations in most organs and upregulated because of injury of organs such as liver, kidney, heart and lung. The function of GDF15 is not fully clear but it seems to have a role in regulating inflammatory pathways and to be involved in regulating apoptosis, angiogenesis, cell repair and cell growth, which are biological processes observed in cardiovascular and neoplastic disorders.