FAM3D (Family with sequence similarity 3, member D, also called EF-7) has been suggested to be new kind of cytokine, because it has a 4-helix bundle structure, which is thought to be unique to growth factors and cytokines. The FAM3 family, consists of four proteins. The receptors and functions of FAM3A, FAM3B, FAM3C are unknown. While FAM3B is found in the pancreas, FAM3D is expressed in the placenta, and FAM3A and FAM3C are ubiquitously expressed (Ref1). The expression of FAM3D is reported to increase in colon cancer patients (Ref2). MBLI's FAM3D ELISA kit can detect FAM3D protein in the culture supernatants of the colon cancer derived cell lines LOVO and WiDr.