Macrophage Migration Inhibitory Factor (MIF) is a pleiotropic cytokine, existing as a homotrimer in vivo. MIF was originally identified as a T cell derived factor responsible for the inhibition of macrophage migration. However, recently MIF has received much more attention because of its possible roles in angiogenesis and cancer development. MIF is over-expressed in various cancers, including pancreatic, breast, colon, brain, prostate, skin, and lung. The intratumoral expression of MIF is strongly correlated with angiogenic growth factor expression, such as the expression of Interleukin 8 (IL-8) and Vascular Endothelial Growth Factor (VEGF), and with risk of recurrence after resection.