HSP90AA1 and neoplasm: It has been demonstrated that cell-impermeable substances inhibiting membrane-associated extracellular Hsp90 (Hsp90-specific antibodies, DMAG-N-oxide, STA-12-7191, and others) reduce cell migration, invasion, and tumor dissemination [19,21,22,24,25], whereas soluble Hsp90 enhances cell migration and invasion [26,27,28].