Monday, April 14, 2008

Sugar and No Exercise Increase Pancreatic Cancer

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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