Rachel's #903: Breast Cancer and Fish

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At 01:25 PM 4/20/07, you wrote:

>Scientific American, Apr. 17, 2007

>[Printer-friendly version]

>

>BRINGING CANCER TO THE DINNER TABLE

>

>Breast Cancer Cells Grow Under Influence of Fish Flesh

>

>By David Biello

>

>Many streams, rivers and lakes already bear warning signs that the

>fish caught within them may contain dangerously high levels of

>mercury, which can cause brain damage. But, according to a new study,

>these fish may also be carrying enough chemicals that mimic the female

>hormone estrogen to cause breast cancer cells to grow.

>

> " Fish are really a sentinel, just like canaries in the coal mine 100

>years ago, " says Conrad Volz, co-director of exposure assessment at

>the University of Pittsburgh Cancer Institute's Center for

>Environmental Ecology. " We need to pay attention to chemicals that are

>estrogenic in nature, because they find their way back into the water

>we all use. "

>

>Volz and colleagues, including biochemist Patricia Eagon, took samples

>from 21 catfish and six white bass donated by local anglers as part of

>a study presented at the American Association for Cancer Research

>meeting in Los Angeles this week. The fish were caught in five places:

>a relatively unpolluted site 36 miles upstream from Pittsburgh on the

>Allegheny River; an industrial site on the Monongahela River; an

>Allegheny site downstream from several industries that release toxic

>chemicals; and the confluence of the Allegheny and Monongahela rivers,

>where Pittsburgh dumps much of its treated sewage and sewer outflows.

> " This is the largest concentration of combined sewer outflows in the

>U.S., " Volz notes, about the confluence, known as the Point. The

>researchers also bought several fish at the store as controls.

>

>Using an organic solvent, the researchers created an extract from the

>skin, flesh and fat of the various fish. They then bathed a breast

>cancer cell line -- known as MCF-7 -- in the extract. " We used this cell

>line because it has estrogen receptors in it, meaning that if

>estrogens are present it causes this cell line to proliferate, " Volz

>explains. " If you put something on it and it grows, then it must be

>stimulating the estrogen receptor. " In addition to responding to pure

>estrogen applied as a positive control, the extract from two of the

>white bass and five of the catfish caused the breast cancer cells to

>thrive.

>

>The highest response came from fish caught in the industrial section

>of the Monongahela River. " The Monongahela River area is the area in

>Pittsburgh that was the site of most of the steel production over the

>last 100 years, " Volz says. " That area is still an industrial

>beehive. " But the broadest response came from where the sewer outflows

>and sewage treatment plants flow into the rivers from Pittsburgh;

>three of the four catfish caught here caused the breast cancer cells

>to proliferate. " Sewage might be more responsible for putting

>estrogenic chemicals in the water than the industries alone, " Volz

>adds. " All of the hormone replacement products that women use go down

>the drain, along with birth control pills, antibacterial soaps, and

>many of the plastics we use, like Bisphenol A, have such effects. "

>

>It remains unclear exactly what estrogen-mimicking chemicals were

>actually present in the fish and what kind of cancer-causing role they

>might have. But their effects on the fish themselves were clear: the

>gender of nine of the fish could not be determined. " Increased

>estrogenic active substances in the water are changing males so that

>they are indistinguishable from females, " Volz says. " There are eggs

>in male gonads as well as males are secreting a yolk sac protein.

>Males aren't supposed to be making egg stuff. "

>

>And this estrogen burden is widespread. The store-bought white bass

>caused breast cancer cells to grow like its river-caught counterparts

>(as well as containing higher levels of mercury, arsenic and other

>contaminants) after being trucked to Pittsburgh from Lake Erie. " These

>fish, again, were in waters that were seeing industrial waste as well

>as possible combined sewer outflows, " Volz notes. " This isn't just

>happening in Pittsburgh, this is happening everywhere in the

>industrialized world. "

>

>Volz says he and his fellow researchers are launching a broader survey

>this summer that will entail sampling fish all along the Allegheny

>River. Efforts will be made to determine if it is industrial waste,

>sewage or agricultural runoff -- or all three -- that is responsible for the

>problem. In the meantime, cooking the fat out of fish may be the best

>defense. " If you broil fish and let the fats drip out that will take

>most of the contaminants out, " Volz says, though that may not be

>enough given other exposures to potentially tainted water. " What our

>study does show us is that there is exposure potential to vast

>populations that use water from our rivers as their drinking water

>supply. "

>

>Copyright 1996-2007 Scientific American, Inc.

 

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