They also found a link between PrPC and heat-shock protein 70 (Hsp70)–Hsp90-organizing protein (HOP, aka stress inducible phosphoprotein 1, STI1 or STIP1), resulting in a modulation of GBM cell proliferation through ERK1/2 and PI3K pathways. The gene discussed is STIP1; the disease is glioblastoma.