Significance of prion and prion-like proteins in cancer development, progression and multi-drug resistance.

Prions are renowned for their role in neurodegenerative diseases in humans and animals. These are manifested as transmissible spongiform encephalopathies (TSEs) that result from the conversion of the normal glycosylphosphatidylinositol (GPI) anchored cellular prion protein (PrP(c)) to a misfolded, aggregated and pathogenic form, prion protein scrapie (PrP(Sc)) via a post-translational process followed by the accumulation of PrP(Sc) within the central nervous system. New research in this area has demonstrated that PrP is over-expressed in a variety of cancers including gastric, pancreatic and breast cancers, affecting the growth and invasiveness of these cancers as well as playing an important role in the acquisition of multi-drug resistant (MDR) gastric cancer.