NCIt definition : A small-molecule inhibitor of heat shock protein 90 (HSP90) with antiproliferative
and antineoplastic activities. Retaspimycin binds to and inhibits the cytosolic chaperone
functions of HSP90, which maintains the stability and functional shape of many oncogenic
signaling proteins and may be overexpressed or overactive in tumor cells. Retaspimycin-mediated
inhibition of HSP90 promotes the proteasomal degradation of oncogenic signaling proteins
in susceptible tumor cell populations, which may result in the induction of apoptosis.;