This document summarizes evidence on potential links between endocrine disrupting chemicals (EDCs) and breast cancer risk. It discusses studies finding associations between breast cancer and exposures like diethylstilbestrol (DES), post-menopausal hormone use, organochlorines like DDT and dieldrin, polychlorinated biphenyls, and chemicals in the home and workplace like phthalates and bisphenol A. While evidence is mixed, some chemicals appear to modestly increase risk, and windows of exposure during development may be important to consider.

1. Breast Cancer – Is there a link to Endocrine Disrupting Chemicals? Suzanne M. Snedeker, Ph.D. Assoc. Director for Translational Research Cornell University’s Program on Breast Cancer and Environmental Risk Factors (BCERF) [email_address] http://www.cfe.cornell.edu/bcerf/

2. 2nd Copenhagen Workshop on Endocrine Disrupters: A Possible Role of Mixed Exposures for Reproductive Failures and Malignancies Session 1: EDC Effects in Humans December 7th, 2002 Rigshospitalet (Copenhagen University Hospital) Copenhagen, Denmark Presented at the:

5. Risks Related to Breast Cancer Advancing Age Genetics Alcohol Hormone Therapy Gender Close Relative Benign Breast Disease Early Menarche Age at First Birth Passive Smoke Education & Income Overweight (post-menopause) Lack of Exercise Chemicals - Work -Home -Garden -Recreation Late Menopause Breast Feeding ??? Diet Ionizing Radiation

7. Endocrine disrupting chemicals – Possible modes of action Breast cancer risk

15. Post-menopausal hormone use – Breast cancer risk, Nurses Health Study Ref: Colditz and Rosner, American J Epidemiology, 152:950-964, 2000 HRT, Estrogen + Prog., 10 yrs ERT, Estrogen unopposed, 10 yrs ERT, Estrogen unopposed, 5 yrs Non-users, solid line

27. Endocrine disrupting chemicals – Phthalates and Premature Thelarche in Puerto Rican Girls Phthalate esters Average conc. in serum, ppb Ref: Colon et al., Environmental Health Perspectives, 108:895-900, 2000

31. Endocrine disrupting chemicals -Understanding susceptibility Ref: Russo and Russo, Oncology Research, 11:169-178, 1999 E2 Growth Hormone IGF Human breast development