Evaluation of Endocrine Therapy Effects of Host Immunity in Early Stage Breast Cancer

The study will enroll mainly subjects with estrogen receptor positive breast cancer that have completed surgery and radiation therapy to remove the tumor(s) and have not yet started standard treatment endocrine therapy. There is one group of subjects who have not been diagnosed with cancer. The information learned from this study will help doctors understand more about how the immune system responds to endocrine therapy for early stage breast cancer in people who are estrogen receptor positive with the goal of developing improved therapies that harness the immune system.