How to Leap from Lipstick to Breast Cancer

Trevor Butterworth

2007 will be remembered as the year that activist groups took work from a handful of scientists that is far from statistically conclusive and went to war on the chemicals in our environment. Not the big nasty chemicals that are burning away the ozone layer or, in the shape of particulate pollution, giving kids asthma, but miniscule amounts of chemicals in everyday consumer products that may be secretly poisoning us.

Like a 1950s B movie, the media can’t resist the chemopocalypse, as Dr. Ben Goldacre points out in his most recent “Bad Science” column for the Guardian newspaper. He cites a recent article from Britain’s Daily Mail newspaper that draws on a new study published in a British online journal by American scientists and which the headline: “Is your lipstick giving you cancer?”

“Chemicals found in lipstick and nail varnish could trigger breast cancer, scientists warned yesterday,” reports the Mail. A study has shown that butyl benzyl phthalate, or BBP, can interfere with the healthy development of breast tissue. Environmental campaigners yesterday called for it to be banned in the cosmetic industry, where it is used to make products glossy.”

Except, as Dr. Goldacre notes, the chemical butyl benzyl phthalate – BPP for short – has already been banned by the E.U.from cosmetics. And STATS has not yet found evidence of it being used in cosmetics in the United States either. It’s mostly used in flooring.

Embarrassing, huh?

But what’s really interesting is whether the study – “The plasticizer butyl benzyl phthalate induces genomic changes in rat mammary gland after neonatal/prepubertal exposure,” by Raquel Moral et al, published in BMC Genomics – really did show a link between BBP and breast cancer or even the risk of breast cancer.

That the authors sometimes fail to write syntactically clear or correct English makes the actual results and argument difficult to follow (the link is to a “provisional” text, so perhaps it has not been fully edited”); Dr. Goldacre appears to believe that BBP is sufficiently risky to merit the ban

But with regard to breast cancer, look what emerges from highlighting (in bold) the degree of qualification and speculation in the text of the study:

Little is known on the effects of BBP on mammary gland, another target of sexual maturity, and the present work indicates that BBP did not induce significant changes in the morphology of that gland, but changed the proliferative index of TEB by 35 days and in Lob1 at 35, 50 and 100 days. Although these modifications are subtle, we cannot rule out that they may have an effect if the mammary gland susceptibility to carcinogenesis, since TEB are the most susceptible epithelial structures to malignant transformation [23] and prevention of chemically-induced mammary carcinomas is accompanied by inhibition of cell proliferation [13, 14].

Changes in the proliferative index of Lob1 in BBP exposed animals in comparison to control group can be associated with subtle alterations in mammary development.

…We are the first to report that neonatal/prepubertal exposure to BBP induced modifications in the gene expression of the mammary tissue. Whereas the full relevance of these findings requires tumorigenesis studies, the characterization of the genomic signature of the mammary gland could be used as a predictor of the susceptibility to carcinogenesis…

…These evidences suggest that genes related to differentiation of the
mammary gland can be very sensitive to the effects of several compounds that may interfere with hormonal action, suggesting that, even if the effects are not strong enough to modify mammary histoarchitecture, they may change the molecular milieu of the gland.

…Hence, although prepubertal exposure to BBP seems to have mainly a transitory effect on the genomic profile of the mammary gland, we cannot discard that subtle changes in the gland may have an effect later in life.

In short, the leap to actual breast cancer is worthy of the late Evil Knievel. But that’s precisely how an otherwise, run-of-the-mill leapt into the media spotlight.

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