HSP90AA1 and cancer: For example, the cytosolic chaperone heat shock protein 90 (Hsp90) represents a promising molecular target for chemotherapeutic intervention due to its causative involvement in the stabilization of mutant client proteins and facilitation of oncogenic signaling cascades, and ansamycin-based and non-ansamycin-based small molecule inhibitors of Hsp90 are currently under clinical evaluation in human cancer patients [11,12].