PRNP and prion disease: Keeping in mind that elevated PrPc levels per se may provoke neurodegeneration,14 that neurodegenerative diseases, including prion diseases are characterized by neuronal apoptosis,19, 20 and that rise in PrPc expression promotes invasiveness and survival of cancer cells,6, 7 the aforementioned conflicting findings on PrPc expression levels and its associated pro- and/or anti-apoptotic properties should be further elucidated.