Astrocyticphosphoprotein PEA-15 (PEA15) is a death effector domain (DED)-containing protein. PEA15 is mainly expressed in the central nervous system, principally in astrocytes. Increased PEA15 levels affect tumorigenesis and cancer progression. PEA15 is overexpressed in breast cancers and gliomas as well as in type 2 diabetes. PEA15 blocks Ras-mediated inhibition of integrin activation and modulates the ERK MAP kinase cascade. PEA15 also inhibits RPS6KA3 activities by holding it in the cytoplasm. In addition, PEA15 inhibits both TNFRSF6 and TNFRSF1A mediated CASP8 activity and apoptosis. At present, PEA15 expression is also a significant prognostic marker in ovarian cancer.