Temsirolimus is an inhibitor of mTOR (mammalian target of rapamycin), a protein that plays a key role in cell growth, division, and survival. By blocking mTOR, temsirolimus interferes with the signals that tell cancer cells to grow and divide. This leads to a halt in the cell cycle (specifically at the G1 phase), preventing tumor cells from multiplying.

In laboratory studies, temsirolimus has been shown to reduce the levels of proteins that help cancer cells survive under low-oxygen conditions and to decrease the formation of new blood vessels that tumors need to grow. Its main use is in cancers where mTOR signaling is abnormally active, such as advanced renal cell carcinoma. Although its primary FDA approval is for kidney cancer, temsirolimus has also been studied in some blood cancers and other solid tumors due to its effects on cell growth and immune function.

temsirolimus

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