Temsirolimus is primarily used as an anticancer medication, specifically for the treatment of advanced renal cell carcinoma (kidney cancer). It works by inhibiting the mTOR pathway, which is crucial for cell growth and proliferation, thereby slowing the progression of cancer. The drug is administered intravenously and is often prescribed when other treatments have not been effective. Additionally, temsirolimus is being investigated for its potential in treating other types of cancers, such as mantle cell lymphoma and certain solid tumors, due to its mechanism of action. Its ability to target specific cellular pathways makes it a valuable option in personalized cancer therapy.