Secreted heat shock protein-90 (Hsp90) in wound healing and cancer

►Normal cells secrete Hsp90 only under a stress, whereas tumor cells secrete Hsp90 always. ►Secreted Hsp90α is an unconventional pro-motility factor, independent of ATPase. ►Secreted Hsp90α, but not conventional growth factors, works against TGFβ inhibition. ► Topical application of Hsp90α protein promotes acute and chronic wound healing. ► Drugs that selectively target F-5 region of Hsp90 may be more effective and less toxic than those targeting the ATPase.