Breast cancer is the most frequently diagnosed cancer in women. Most breast cancer are hormone receptor-positive (estrogen and/or progesterone receptor-positive) and need hormones to grow. After surgery, those cancers can be treated by various hormone therapy which include modulators and degraders of estrogen receptors, and blockers of estrogen production. Although with generally favorable outcome, certain percentage of those cancers develop resistance to hormone therapy, which rises the risk of breast cancer recurrence, breast cancer in the opposite breast, and death from breast cancer. For those cases it is important to understand mechanisms that caused resistance, to identify biomarkers which could predict the resistance development, and finally, to discover more efficient combined therapy or improved follow-up protocol.

In this project, we propose a research based on established estrogen-positive breast cancer cell lines and breast cancer clinical samples to decipher in more detail how endocrine resistance emerges. Cell-based experiments would lead to the discovery of more efficient combined therapy and experiments involving real clinical breast cancer samples will be used for identification of biomarkers that could predict which tumor will develop endocrine resistance. Results of our proposed project could ultimately lead to improved treatment and even better outcome of patients with hormone receptor-positive breast cancers.