How aspirin may stem cancer

The use of aspirin and other nonsteroidal anti-inflammatory drugs significantly reduces the risk for cancer, but no one has been able to explain why. Now researchers have found that these drugs slow the accumulation of a type of DNA change called somatic genome abnormalities, or SGAs, that lead to uncontrolled cell growth. The scientists studied 13 people with Barrett’s esophagus, a condition in which cells in the esophagus become damaged, usually by acid reflux. Sometimes the cells become precancerous, and rarely the problem leads to esophageal cancer.

The researchers tracked SGAs with periodic biopsies over an average of almost 12 years. Overall, the use of nonsteroidal anti-inflammatory drugs was associated with a 90 per cent reduction in the rate of mutations.

“We used techniques used to measure mutation rate in viruses like HIV to measure it in humans,” said the senior author, Carlo C Maley, director of the Center for Evolution and Cancer at the University of California, San Francisco.

“We measured whole pieces of chromosomes that are getting deleted or copied.” Apparently aspirin slows that rate of mutation.

The study, published last month in the journal PLoS Genetics, is very small, Maley said, and has yet to be reproduced in a larger population. But since most cancers take decades to develop, he added, “If you could just slow it down, you could slow it enough to have people die of something else.”

Male infertility tied to cancer

Studies have shown that male infertility is associated with a slightly increased risk for various types of cancer, including testicular cancer, possibly because of shared genetic factors.

About one in six infertile men have azoospermia, or no viable sperm in their ejaculate, and these men may be at the highest cancer risk, a new study shows. For the study, published online in the journal Fertility and Sterility, researchers evaluated 2,238 men, average age 36, at a fertility clinic in Texas; 451 had azoospermia. They found 29 cases of cancer during an average follow-up of almost seven years. Overall, those in the infertile group were 1.7 times as likely as the general population in Texas to develop some form of cancer. But the risk more than tripled for those with azoospermia.

While the increase in relative risk is substantial, the authors write, the absolute risk of cancer in this population remains low. “The main message here is to continue follow-up after a fertility workup,” said the lead author, Dr Michael L Eisenberg, an assistant professor of urology at the University of Stanford. “This is not a screen for health, but it may be a warning sign of other things,” author Eisenberg said.

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