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    Global taskforce of scientists finds that current chemical safety testing is inadequate

    Global taskforce of scientists finds that current chemical safety testing is inadequate

    June 23, 2015 (San Francisco, CA)

    Challenging the current paradigm for testing environmental chemicals individually, an international team of 174 scientists meeting under the auspices of the non-profit group Getting to Know Cancer, has published a new assessment of mixtures of chemicals acting synergistically to potentially contribute to cancer development.

    The findings were published online today along with 11 supporting documents in Carcinogenesis.

    The scientists found that 50 widely used chemicals that are not considered carcinogenic to humans affected one or more of the ’hallmarks of cancer’—processes that occur during the development of human tumors. Further, that a mixture of several of these common chemicals may act in concert to cause cancer, even though low-level exposure to the chemicals individually might not be carcinogenic.

    “Current chemical safety testing is outdated and largely ignores the possibility that chemicals might act synergistically, so our study presents a game-changing concept. Every day we are exposed to an environmental ’chemical soup’, and we need to start testing the effects of the mixtures of chemicals in that soup,“ said Dr. William Goodson, M.D., Senior Scientist at California Pacific Medical Center Research Institute and lead author of the summary paper for the group consensus.

    “Combinations of disruptive chemicals—those that together impinge on the key pathways underlying hallmarks of cancer—should be studied more rigorously and guidelines adapted to build a new framework for understanding the impact of low-dose mixtures of environmental chemicals.”

    In the study, scientists from 26 prominent research centers worldwide reviewed data on 85 commonly encountered chemicals and assessed their effects on mechanisms related to carcinogenesis. Sources of data included reviews and original studies. Fifty of these chemicals are already known to have low-dose effects, but have been presumed to be safe individually.
    Working in 11 groups, the scientists tabulated these known effects of low-dose exposures on different molecular targets and tissues, and found that mixtures of these chemicals working together might be sufficient to cause cancer, even if no single chemical was sufficient alone. The also sought ‘cross-hallmark’ effects whereby one chemical disrupted more than one essential aspect of cellular physiology. The investigators then categorized each chemical according to the relevance and relative strength of evidence underlying each chemical.

    “This supports an urgent need for research on the carcinogenic effects of low-dose chemical mixtures. Our findings are a call-to-action for international regulatory agencies to revise their current frameworks for testing environmental chemicals.”

    Studies from the World Health Organization (WHO) and the International Agency for Research on Cancer suggest that between seven to 19% of cancers are attributable to toxic environmental exposure.

    The study was supported by the National Institute for Environmental Health Sciences and Getting to Know Cancer.