The Multifaceted Functions of Prion Protein (PrP C ) in Cancer.

The cellular prion protein (PrP C ) is a glycoprotein anchored to the cell surface by glycosylphosphatidylinositol (GPI). PrP C is expressed both in the brain and in peripheral tissues. Investigations on PrP C 's functions revealed its direct involvement in neurodegenerative and prion diseases, as well as in various physiological processes such as anti-oxidative functions, copper homeostasis, trans-membrane signaling, and cell adhesion. Recent findings have revealed the ectopic expression of PrP C in various cancers including gastric, melanoma, breast, colorectal, pancreatic, as well as rare cancers, where PrP C promotes cellular migration and invasion, tumor growth, and metastasis. Through its downstream signaling, PrP C has also been reported to be involved in resistance to chemotherapy and tumor cell apoptosis. This review summarizes the variance of expression of PrP C in different types of cancers and discusses its roles in their development and progression, as well as its use as a potential target to treat such cancers.