Microorganisms in the human body (such as virus, bacteria, fungus) may have an important role in breast cancer side effects. In this study, microorganisms will be analyzed to determine which, if any,are present. It will then be determined if side effects from breast radiation are associated with these microorganisms. Understanding the association of microorganisms with side effects will allow the study team to look at strategies to reduce side effects for patients undergoing radiation to the breast.

This study will prospectively enroll 50 participants with with biopsy proven Ductal carcinoma in situ (DCIS) or invasive breast cancer 18 years of age or older, undergoing breast conserving surgery and adjuvant radiation therapy at Cleveland Clinic.

Each participant will have a post-surgery pre-radiotherapy stool and breast skin sample obtained, complete a medical record review for clinical data, and have complete an interview/questionnaire in order to learn about potential risk factors which will be included in the data collection form. Included information will include Stage (T, N, M, composite), receipt of chemotherapy, radiation fields and dose, BMI, hypertension (HTN), Diabetes Mellitus (DM), smoking status, history of breast infection yes/no (Data Collection Form).

Inclusion Criteria:

• Breast cancer patients with DCIS or invasive breast cancer
• Undergoing breast conserving surgery and adjuvant radiation
• Subjects must be willing and able to provide breast skin samples

Exclusion Criteria:

• Active clinical breast infection (on antiobiotic for skin/breast infection or clinical diagnosis)
• Refuse or are unable to sign informed consent form
• Past history of breast cancer

Patients with biopsy proven DCIS or invasive breast cancer, 18 years of age or older, undergoing breast conserving surgery and adjuvant radiation therapy at Cleveland Clinic.