Patient description: The patient is a 37-year-old woman who came to the clinic for a routine Pap smear. The test revealed stage 1B of cervical cancer. The patient tested positive for HPV 16. She has three sexual partners and four children. She underwent tubal ligation. She smokes 30 packs/year and drinks alcohol frequently. She is otherwise healthy. She was offered a radical hysterectomy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Breast Ductal Carcinoma In Situ Breast Lobular Carcinoma In Situ Stage 0 Breast Cancer AJCC v6 and v7 Stage I Breast Cancer AJCC v7 Stage IA Breast Cancer AJCC v7 Stage IB Breast Cancer AJCC v7 Stage II Breast Cancer AJCC v6 and v7 Stage IIA Breast Cancer AJCC v6 and v7 Stage IIB Breast Cancer AJCC v6 and v7 Stage III Breast Cancer AJCC v7 Stage IIIA Breast Cancer AJCC v7 Stage IIIB Breast Cancer AJCC v7 Stage IIIC Breast Cancer AJCC v7 Women scheduled for unilateral or bilateral mastectomy for breast cancer therapy, pathology confirmed stage 0-III (including ductal carcinoma in situ), or prophylaxis (BRCA1/2 mutation carriers, women with strong family history or lobular carcinoma in situ or other conditions where prophylactic mastectomy has been elected) Eastern Cooperative Oncology Group (ECOG) performance status =< 1 (Karnofsky >= 70%) Total bilirubin < 1.5 x upper limit of normal (ULN) (in women with prior documented bilirubin elevations consistent with Gilbert's syndrome, total bilirubin up to 3 x ULN will be allowed) Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT]) < 2.5 x ULN Alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) < 2.5 x ULN Creatinine < 2 x ULN Alkaline phosphatase < 2.5 x ULN Blood urea nitrogen < 2 x ULN Ability to understand and the willingness to sign a written informed consent document which includes a requirement to apply study agent to sensitive body parts daily Willingness and ability to schedule mastectomy 21-28 days following start of study agent; women with breast implants may participate  The presence of gross skin invasion/ulceration by the breast cancer, or inflammatory changes with skin edema AND erythema; Note: Paget's disease is permitted Women receiving a "nipple delay" procedure prior to mastectomy Women with skin diseases (psoriasis, eczema) A history of thromboembolic disorder Endometrial intraepithelial neoplasia (also known as atypical hyperplasia) or a high risk of uterine cancer, defined here as known carriers of Lynch syndrome mutations (MLH1, MSH2, MSH6, PMS2) Participants may not have received any other investigational agents in the previous 3 months History of allergic reactions attributed to compounds of similar chemical or biologic composition to tamoxifen Taken tamoxifen or other selective estrogen/progesterone receptor modulators (SERMs/SPRMs) within two years prior to entering study or been required to discontinue SERM therapy due to thromboembolic or uterine toxicity Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements History of prior breast cancer-specific therapy within the previous 2 years (chemotherapy, radiation, anti-HER2 agents, endocrine agents, everolimus, CDK4-6 inhibitors); previous unilateral radiation of the contralateral side in women scheduled for mastectomy is allowed; study gel will be applied to both breasts