[Pharmwaste] Bringing Cancer to the Dinner Table: Breast Cancer Cells Grow Under Influence of Fish Flesh

[DeBiasi,Deborah]

http://www.sciam.com/article.cfm?articleID=01DC8631-E7F2-99DF-3D0A925F84
E60223&chanID=sa003    

 
April 17, 2007   
 
Bringing Cancer to the Dinner Table: Breast Cancer Cells Grow Under
Influence of Fish Flesh   
 
Tests of river fish indicate their flesh carries enough
estrogen-mimicking chemicals to cause breast cancer cells to grow   
 
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. "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." 

 

Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
Mail:          P.O. Box 1105, Richmond, VA  23218 (NEW!)
Location:  629 E. Main Street, Richmond, VA  23219
PH:         804-698-4028
FAX:      804-698-4032