KW-2478 (CAS 819812-04-9) is a potent non-ansamycin inhibitor of heat shock protein 90 (Hsp90) Unlike traditional Hsp90 inhibitors such as 17-AAG KW-2478 exhibits improved aqueous solubility and reduced hepatotoxicity In multiple myeloma cell models KW-2478 induces degradation of Hsp90 client proteins and leads to downregulation of IgH translocation products including FGFR3 c-Maf and cyclin D1 thereby inhibiting cell proliferation and promoting apoptosis Additionally KW-2478 reduces levels of Cdk9 and phosphorylated 4E-BP1 further suppressing oncogenic transcriptional regulators This compound is a valuable tool for studying Hsp90-mediated pathways and evaluating therapeutic strategies in hematological malignancies