This gene encodes a tumor suppressor protein that selectively induces apoptosis in cancer cells through intracellular and extracellular mechanisms. The intracellular mechanism involves the inhibition of pro-survival pathways and the activation of Fas-mediated apoptosis, while the extracellular mechanism involves the binding of a secreted form of this protein to glucose regulated protein 78 (GRP78) on the cell surface, which leads to activation of the extrinsic apoptotic pathway. This gene is located on the unstable human chromosomal 12q21 region and is often deleted or mutated different tumors. The encoded protein also plays an important role in the progression of age-related diseases. [provided by RefSeq, Aug 2017]