Despite remarkable improvements in treatment options, development of endocrine resistance is one reason that breast cancer is the second most frequent cause of cancer death in women. In most cases, estrogen receptor (ER) is present in these resistant tumors, and in many ER continues to regulate tumor growth. This project aims to develop a new clinical-translational strategy to address this challenge and promote patient survival. Dr. Pietras plans to develop a new generation of selective ER downregulators (termed SERDs) with the proper biologic/pharmacologic profile to be used as therapeutics for endocrine-sensitive and -resistant cancers in clinic.