How Tamoxifen Raises Uterine Cancer Risk—and a Path to Prevention

Tamoxifen has been a cornerstone of breast cancer treatment for more than four decades, saving countless lives as one of the earliest and most effective targeted cancer therapies. But while the drug dramatically reduces the risk of breast cancer recurrence, it also carries a well-documented side effect: women taking tamoxifen face a two- to seven-fold increased risk of developing uterine cancer compared to the general population.

Until now, the biological mechanism behind this elevated risk remained an open question. A new study led by researchers at Mass General Brigham, the Broad Institute of MIT and Harvard, Dana-Farber Cancer Institute, and the Berlin Institute of Health at Charité (BIH) has uncovered how tamoxifen drives this secondary cancer risk—and points to a potential way forwar