Breast cancer science: New reports show that federal policy on chemicals testing neglects breast health.

What women really think about news, politics, and culture.
June 27 2011 2:45 PM

Scientists to Chemical Regulators: Stop Ignoring Boobs

A new set of reports shows that federal policy on chemicals testing neglects breast health.

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"I wish I could understand the failure of logic in not testing mammary glands," says Jeanne Rizzo, director of the Breast Cancer Fund, a California-based nonprofit. But she says she's heartened that the discussion is even on the table. "Ten years ago, when we said we need to look at the environment and we need to look at prevention, people thought we were nuts."

It's becoming increasingly clear, though, that mammary glands belong on a slide and not in the dumpster. Recent studies show that some pesticides, pharmaceuticals, and plastic additives appear to change when and how the mammary gland develops. Even low doses, close to what average Americans are exposed to currently, have been linked to altered development, cell growth, and gene expression in animal mammary glands. The chemicals include the notorious baby-bottle chemical bisphenol A, dioxin (a by-product from burning plastic and a common food contaminant), phthalates (plastic additives), atrazine (a top-selling herbicide in the United States, now banned in Europe), flame retardants, and stain repellants. PFOA, a common chemical used to make Teflon, appears to delay puberty in animal pups and reduce the size of the mammary gland, while chemicals that mimic estrogen may accelerate puberty.

The good news is that the mounting data on the sensitivity of breast cells has caught the attention of scientists within state and federal government. Some are calling for reform. "There's a growing body of animal evidence and sporadic human evidence that things we're exposed to across a lifetime can cause breast cancer," says Marion Kavanaugh-Lynch, director of California's Breast Cancer Research Program, a governmental grant-making organization that helped fund the 2009 workshop with proceeds from the state's cigarette tax. "If we can identify these chemicals now, we can more easily avoid them," she says.

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The question is whether, and how fast, regulatory agencies can update their toxicity protocols. New tests have to be proven effective and then standardized across numerous labs. In a victory for breast-cancer advocates, the National Toxicology Program, under pressure from its own scientists, is actively rewriting its testing guidelines to look more carefully at mammary glands. But this is only a partial victory, as the NTP does not have the authority to regulate chemicals (it's a research and advisory body), and the agency tests only about six to eight substances per year.

The NTP's Fenton is a big fan of a new testing procedure, the gruesome-sounding "whole mount," a way of preparing dissected rodent tissue to look for changes both subtle and overt. A rodent's fourth or fifth mammary glands—those near the stomach—are removed, flattened, stained, and mounted flat to a slide, where they can be carefully examined for changes in cells or structures. Soon, Fenton hopes, every government lab will use it. If approved, NTP's guidelines would also require that certain tests include doses of chemicals both in-the-womb and around the time of puberty.

The EPA is watching closely to see if and how the NTP's new tests pass political and scientific muster. So is the Organisation for Economic Cooperation and Development, which guides chemicals testing in Europe. With added data from mammary glands, policymakers could have more reasons to keep unsafe substances off the market. If your breasts won't benefit, your daughters' just might.