PRNP and cancer: The constitutive, tight association between PrPC and lipid rafts [326,513] and its wide expression in stem cells [8,514,515,516,517] offer additional insight as to how prions interact with membrane supramolecular complexes [518] to participate in an extensive range of physiological functions including transcription, scaffolding, and signaling [267], and modulate cancer stemness, differentiation, self-renewal, and proliferation to augment cancer MDR [65,71,77,516,519,520].