Changing how chemicals are screened for breast cancer risk: Test driving the recommendations of the breast cancer and chemicals policy project

Breast cancer, the most common invasive cancer in women, is hypothesized to be linked to industrial chemical exposure through the environment and the use of consumer products. A major challenge in understanding the extent to which chemicals contribute to breast cancer is a lack of toxicity information—a data gap—for tens of thousands of commonly used chemicals. The Breast Cancer and Chemicals Policy (BCCP) project was designed to streamline this process by identifying biological pathways linked to the development or progression of breast cancer and the corresponding test methods to assess perturbations of these pathways (see abstract #286539, first author M Schwarzman). The Hazard Identification Approach (HIA) developed by the BCCP expert panel highlighted the need to assess chemicals for their contribution to endocrine disruption, genotoxicity, apoptosis and uncontrolled cell division. To validate the HIA, we conducted a "virtual" pilot test, investigating how well-studied chemicals would perform if tested according to the HIA. Chemicals were chosen based on authoritative body designation by IARC or NTP and included known mammary carcinogens, known carcinogens, suspected mammary carcinogens and chemicals not recognized as carcinogens. Assays for the endpoints were chosen based on existing protocols such as EPA's Tier 1 Endocrine Disruptor Screening Program or commonly used assays for assessing genotoxicity. A literature review for each of the assays and chemicals identified those chemicals with evidence of a measureable effect, evidence of no effect, or a lack of evidence. These were compiled into a table to identify overall trends. This presentation will summarize the results of the pilot screen and how well the HIA designed by the BCCP panel will perform in assessing the links between chemicals and breast cancer.