Effects of Endocrine Therapies in Early Stage ER+ Breast Cancer - Clinical Trial

Women with breast cancer will have a total of 4 blood draws and be asked to answer questionnaires.

Women without breast cancer ("healthy group") will have 4 blood draws and be asked to complete medical questionnaires.

Pre- and Post-menopausal women with early stage ER+ breast cancer starting endocrine therapy

Adult women with early stage breast cancer who:
- Are estrogen receptor positive
- Have plans to start endocrine therapy
- Are on hormonal birth control if you are a healthy patient

We are doing this blood and tissue sample study to learn how endocrine therapy affects immune cells in women. Women with breast cancer will be compare to women without cancer.