Retaspimycin Hydrochloride is primarily investigated for its potential in cancer therapy. It functions as an inhibitor of heat shock protein 90 (HSP90), a chaperone protein that assists in the proper folding and stabilization of various client proteins, many of which are involved in cancer cell survival and proliferation. By inhibiting HSP90, Retaspimycin Hydrochloride disrupts the stability and function of these client proteins, leading to the degradation of oncogenic proteins and ultimately inducing cancer cell death. This mechanism makes it a promising candidate for treating various types of cancers, including solid tumors and hematologic malignancies. Clinical studies are ongoing to evaluate its efficacy and safety in combination with other anticancer agents or as a standalone therapy. Its application is particularly focused on cancers that are resistant to conventional treatments, offering a potential avenue for overcoming drug resistance.