"Until recently, tamoxifen was known primarily for its ability to block estrogen receptors on the outside of cancer cells. However, new studies have suggested that when tamoxifen is given in higher doses, it works through a second mechanism of action independent of the estrogen receptor. This second mechanism was the focus of the Rochester laboratory.
Led by doctoral student Hsing-Yu Chen and Mark Noble, Ph.D., professor of Biomedical Genetics at URMC, the team studied the molecular mechanism that allows basal-like breast cancer cells to escape the secondary effects of tamoxifen, and discovered that two proteins are critical in this escape. One protein, called c-Cbl, controls the levels of multiple receptors that are critical for cancer cell function. A second protein, Cdc42, can inhibit c-Cbl and is responsible for the tumor’s underlying resistance."