Compounds found in plastic food packaging could be possible cancer-causing
agents, according to a worrying new study from the US.
Researchers at Fox Chase Cancer Center in Philadelphia, US claim to have demonstrated
that two plasticiser compounds, BPA and BBP, are environmental estrogens capable
of affecting gene expression in the mammary glands of young female laboratory
rats exposed to the compounds through their mothers' milk.
Plastic products used to wrap or contain food and beverages have therefore
aroused concerns as possible cancer-causing agents because they can sometimes
leach out of the plastic and migrate into the food.
The scientists found that this was especially true after heating or when the
plastic is old or scratched.
"Development of breast cancer entails multiple events, in which estrogen
appears to play an important role," said Jose Russo, director of the Breast
Cancer and the Environment Research Center at Fox Chase.
"Estrogenic agents involved in breast development and possibly in breast
cancer may include foreign estrogens, or xenoestrogens, that are used in manufacturing
a number of products. The studies of BPA and BBP in young rats were designed
to see whether exposure to these hormonally active biological compounds could
alter the genomic signatures of the mammary gland during critical stages of
BPA (bisphenol A) is a synthetic resin used in food packaging and polycarbonate
plastic products. BBP (n-butyl benzyl phthalate) is a widely used plasticiser
used in food wraps and cosmetics.
"In exposing prepubescent female rats to BPA and BBP, our aim was to determine
what effects, if any, each compound had on mammary gene expression during at
different ages," said postdoctoral associate Raquel Moral.
"Our results showed that exposure to BPA changes the gene expression profile
of mammary tissues as a function of age. That is, there was a significant increase
in protein production governed by various genes at increasing ages from 21 to
These included proteins regulating cell proliferation and differentiation,
including tumour-suppressing proteins and a large number of unknown proteins.
The exception was decreased expression of the GAD1 gene. It encodes a key enzyme
of the GABA-ergic system, which could be involved in hormonal regulation and
breast cancer development. GAD1 has consistently been overexpressed in primary
"In contrast, the BBP exposure modified the genomic signature of the mammary
gland primarily at 21 days of age and had less effect later," said Moral.
However, future studies are needed to determine whether exposure to such xenoestrogens
leads to breast cancer in rats and whether these estrogens bring about similar
gene alterations in human breast tissue.