Why the UN Treaty on Plastics Can Reduce Early Onset Cancers
Cancer rates continue to increase around the world, particularly in younger people. (1) Women are twice as likely as men to be diagnosed with cancer before age 50, and breast cancer diagnoses are a major contributor to the incidence of early onset disease. (Cancer registry data are limited to these gender categories.) Well-studied breast cancer risk factors such as having fewer children cannot fully explain these trends, (2) supporting a need to examine breast cancer-relevant chemicals (BCRCs) in food, water, and consumer products as likely factors.
Recently, we identified 920 BCRCs on the basis of evidence that they induce mammary tumors in rodents or have specific endocrine-disrupting effects. (3) Nearly half (414) of these chemicals are found in plastics, highlighting how the United Nations (UN) Intergovernmental Negotiating Committee on Plastic Pollution, which is meeting this month about a new treaty, can reduce the burden of breast cancer and other health conditions.
We compared our list of BCRCs to data from the PlastChem project, (4) an initiative by primarily academic and nonprofit researchers to create a database of more than 16 000 chemicals used in plastics. Of the 414 chemicals on both lists, 98 cause mammary tumors in rodent studies, 188 increase the level of estradiol synthesis, 132 increase the level of progesterone synthesis, and 149 activate the estrogen receptor (Supporting Information). Each of these types of biological activity is an established pathway to breast cancer. (3) Of the 341 endocrine-active BCRCs in plastics, 166 have a robust response in vitro while 175 have borderline activity that requires additional testing (Figure 1). Moreover, 160 of these endocrine-active chemicals are also genotoxic, another mechanism for carcinogenesis. Overall, we prioritized 175 potential breast carcinogens in plastics for regulation and reduction due to evidence that they cause mammary tumors or have robust hormonal activity combined with genotoxicity.
