Abstract: High throughput methods for identifying novel inhibitors of Hsp90 chaperone protein folding are disclosed. The inhibitors so identified disrupt the binding of p23 to either Hsp90? or Hsp90? and have selective activity against the proliferation of cancer cells. In particular are provided embodiments of therapeutic compositions that comprise at least one inhibitor of an Hsp90 chaperone activity, the inhibitor being any of the compounds designated as CP1-CP19 as shown in FIGS. 1A-1D or a 2-(trifluoromethyl)pyrimidin-2-yl)thio)acetamide derivatives.