Breakthrough study of hormone ’crosstalk’ in breast cancer

(Image: Pixabay CC0) - Scientists led by EPFL have successfully engrafted breast cancer cells on mice, allowing them to study in vivo the cross-talk between the estrogen and progesterone receptors that hampers hormone therapies. Their findings suggest that endocrine therapy may need to be personalized, and that abrogating progesterone receptor expression can be a therapeutic option. "Breast cancer affects 1 in 7 women," says Professor Cathrin Brisken at EPFL's School of Life Sciences. "More than two thirds of the cases are hormone-sensitive and express the receptor for estrogen in more than 1% of the tumor cells." In fact, biological signaling by the estrogen receptor is a key driver of breast carcinogenesis and blocking it is a standard pursuit of hormone therapies, which have substantially improved survival rates of patients. The problem is that tumors that are positive for the estrogen receptor have been understudied because the field lacks adequate animal models. "Mammary carcinomas that develop in genetically engineered mouse models are not sensitive to hormones, and the rates for successful estrogen receptor-positive breast cancer xenografts are extremely low." Previous studies have revealed an important "crosstalk" between the estrogen receptor with another sex hormone, progesterone. Specifically, the biological signaling pathways of the estrogen and progesterone receptors seem to interfere with each other both on a genomic and protein level.