Celastrol (8, Figure 4) is a quinone methide triterpene isolated from the Tripterygium wilfordii Hook F. In pancreatic cancer cells, celastrol disrupts the Hsp90–Cdc37 interaction, but does not disrupt Hsp90–Hop and Hsp90–p23 interactions [69]. The gene discussed is CDC37; the disease is familial pancreatic carcinoma.