Tamoxifen Treatment Impact in Breast Cancer Patients

Inclusion Criteria: * Female * Age criteria for pre-menopausal group: Equal to or greater than 18 years of age and less than or equal to 45 years of age. Patients of age 46-50 will be included if they have not had menstrual cessation for 12 consecutive months. * Age criteria for menopausal group: At least 51 years of age (median age of menopause). Menopause is defined as cessation of menstrual cycle for 12 consecutive months. * Diagnosed with ER+ breast cancer * Being treated with tamoxifen (TAM) for at least 6 months * CONTROL SUBJECTS: Newly diagnosed ER+ breast cancer patients of the same age group as above on TAM for 0-6 months. This criterion is based on our preliminary results showing that patients taking TAM for 6-7 months exhibit near baseline level of NETs Exclusion Criteria: * Pregnant -The immune modulations geared toward maintenance of pregnancy are known to cause wide-spread alterations in innate and adaptive immune cell functions. In this scenario, divorcing the pregnancy-related changes in myeloid cell function from those relevant to sepsis and cancer will be complicated. * History of severe congenital neutropenia due to genetic disorders, such as Kostmann Disorder (HAX1 gene mutation), ELA2 gene mutation, Wiskott-Aldrich syndrome (WAS), Growth Factor Independent 1 Protein (GFI1) gene mutation, Colony Stimulating Factor 3 Receptor (CSF3R) gene mutation, Schwachman-Diamond Syndrome, Barth Syndrome, WHIM Syndrome, and Chadiak-Higashi Syndrome (this list notably does not include Myelodysplastic Syndrome, or Acute/Chronic Myeloid Leukemia) * History of autoimmune disorders, which can affect the body's inflammatory response, such as rheumatoid arthritis, lupus, Crohn's disease, multiple sclerosis, and psoriasis. * History of chronic viral infections (human immunodeficiency virus \[HIV\], hepatitis), which can lead to reduced or variable immune cell function. * A recent positive coronavirus disease (COVID) test