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Obesity and physical inactivity contribute
to the risk of cancer of the pancreas.
The body becomes less sensitive to the
glucose-lowering effects of insulin with obesity and inactivity,
and diminished sensitivity to insulin leads to higher blood
levels of insulin. Higher levels of insulin are thought to
increase the risk of cancer of the pancreas.
But previous attempts to link inactivity
and obesity with pancreatic cancer brought inconsistent results.
The investigators used body mass index (BMI), a measure of
weight in relation to height, to determine whether or not
patients were obese.
Men
and women with high BMI faced a pancreatic cancer risk 1.5
to 2 times higher than those with low BMI.
Dieting, however, apparently lowered
the risk, the report indicates, as both men and women who
reported a 10% to 12.5% decrease from their maximum lifetime
weight had only about half the risk of cancer of the pancreas
faced by others.
Exercise lowered the risk. The researchers
note that men who exercised strenuously at least 8 hours a
month had only 59% of the pancreatic cancer risk of men who
exercised less.
International
Journal of Cancer 2001;94:140-147
Gene Therapy May
Destroy Pancreatic Cancer Cells
Using a new two-pronged attack, researchers
were able to destroy deadly pancreatic cancer cells
in the test tube and in lab animals.
Researchers were interested in using
a tumor-stopping protein from a newly discovered gene known
as mda-7, which has been found effective in destroying other
types of cancer cells.
However, the investigators had previously
found that mda-7 alone, delivered to pancreatic cancer cells
in the lab, could not destroy the cancer cells.
In this study, they added a small piece
of DNA that blocked the expression of the K-ras gene to the
mda-7. The K-ras gene is associated with uncontrolled cell
growth when mutated, and it is mutated in 85% to 95% of pancreatic
cancer cells, including the cells the experimenters used.
The combination of the two killed
the pancreatic cancer cells in the lab after a
few days, Lebedeva said. The researchers also found the combination
killed tumor cells in lab animals.
Proceedings
of the National Academy of Sciences 2001;98:10332-10337
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