Tamoxifen is a selective estrogen receptor modulator that can be used orally. It is the most sold and used drug in breast cancer treatment worldwide.
Tamoxifen is designed to block estrogen receptors on the surface of breast cancer cells. Estrogen hormone, which is a growth factor, binds to the estrogen receptor (ER), which is located on the surface of the cell and is also known by its name, and enables normal breast cells to grow. In the case of breast cancer, estrogen receptors work for the growth and proliferation of cancer cells. In the majority of breast cancer types, tumor cells have significantly increased the number of estrogen receptors in their membranes and have become estrogen-dependent to grow. This type of breast cancer is called hormone positive breast cancer. Tamoxifen inhibits the binding of estrogen to its receptor and stops the growth of breast cancer cells. Can be used by both pre-menopausal and post-menopausal patients