17-AAG is a less toxic and more stable analog of geldanamycin. 17-AAG is an Hsp90 inhibitor that displays a 100-fold higher affinity for Hsp90 derived from tumor cells compared to Hsp90 from normal cells. 17-AAG inhibits Akt activation and expression in tumors and synergizes with a number of anti tumor agents such as taxol2, cisplatin3, and UCN-014. 17-AAG causes the inactivation, destabilization and eventual degradation of HIF-1α5. In the prostate, 17-AAG can inhibit the growth of cancer cell lines.