July 28, 2021 | Research published in Environmental Health Perspectives finds nearly 300 different chemicals, in pesticides, consumer products, and contaminated resources (e.g., food, water) increase breast cancer risks. Breast cancer is the most common cancer among women, causing the second most cancer-related deaths in the U.S. Genetic factors only play a minor role in breast cancer incidence, while exposure to external environmental factors (i.e., chemical exposure) may play a more notable role. Using high throughput screening (HTP) data from an in vitro ToxCast assay (test) developed by EPA, researchers identified chemicals that increase estradiol (a type of estrogen) or progesterone production in H295R cells responsible for hormone synthesis. [Cardona, Bethsaida and Rudel, Ruthann. Application of an in Vitro Assay to Identify Chemicals That Increase Estradiol and Progesterone Synthesis and Are Potential Breast Cancer Risk Factors. Environmental Health Perspectives. 129(7) July 2021]