Plastic chemical may up cancer risk in womb

Pregnant women who drink from plastic bottles may be increasing their baby's risk of developing cancer later in life, a new study has warned.
Researchers from University of Illinois in Chicago found that early exposure to BPA (bisphenol A) - an additive commonly found in plastic water bottles and soup cans - causes an increased cancer risk in an animal model of human prostate cancer.
"This is the first direct evidence that exposure to BPA during development, at the levels we see in our day-to-day environment, increases the risk for prostate cancer in human prostate tissue," said researcher Gail Prins, professor of physiology and director of the andrology laboratory in urology at the UIC College of Medicine.

The increased risk can be traced to prostate stem and progenitor cells which become "sensitised" to estrogen early in development through exposure to BPA - which mimics estrogen in the body.
Environmental exposure to compounds like BPA that mimic hormones has become common, said Prins.
Prostate stem cells, which are very long-lived, pass on the increased estrogen sensitivity to the prostate tissues they produce throughout life.

Because prostate cancer is fuelled in part by naturally rising estrogen levels in ageing men, the prostate tissue's increased sensitivity to estrogen makes the development of cancer much more likely, according to Prins.
"Studies of expectant mothers in the US showed that more than 95 per cent of them had BPA in their urine, which means they recently ingested these compounds," Prins was quoted as saying by the 'Daily Express'.

Previous studies by Prins and colleagues using rats showed that exposure to elevated estrogen or BPA during embryonic development increased the rate of prostate cancer later in life.
To determine if there was a link in humans, Prins developed a new animal model using human prostate stem cells implanted into mouse 'hosts'.
Prins took human prostate stem cells from deceased young adult male organ donors and implanted the cells into mice, where they formed human prostate tissue.
To mimic exposure to BPA during early prostate development, Prins fed the mice BPA for the first two weeks after the transplant, at doses in line with those seen in pregnant American women. The tissue was then allowed to mature for a month into a human prostate-like tissue.

Next, Prins exposed the mice to elevated estrogen levels for two to four months, to mimic the normal rise in estrogen seen in ageing men.
Signs of cancer developed in the human prostate tissue in a third of the mice fed BPA, as compared to only 12 per cent in mice that had not been fed BPA. If the stem cells were exposed to BPA before implantation and again during development, 45 per cent showed signs of cancer.