KW-2478 is a potent inhibitor of heat shock protein 90 (Hsp90), a molecular chaperone involved in the stabilization and function of various client proteins that play critical roles in cell signaling, proliferation, and survival. Due to its ability to disrupt Hsp90 activity, KW-2478 has been investigated primarily for its antitumor properties. It induces the degradation of Hsp90-dependent client proteins, many of which are oncogenic drivers in cancers such as leukemia, breast cancer, and non-small cell lung cancer. In preclinical studies, KW-2478 demonstrated significant antiproliferative effects in cancer cell lines and tumor xenograft models, particularly in hematological malignancies. Its mechanism leads to cell cycle arrest and apoptosis in tumor cells, making it a candidate for targeted cancer therapy. Research has also explored its use in combination with other anticancer agents to enhance therapeutic efficacy and overcome drug resistance. Due to its selectivity and activity profile, KW-2478 has served as a valuable tool compound in oncology research, helping to validate Hsp90 as a therapeutic target and guiding the development of next-generation Hsp90 inhibitors.