Smoking erases Y chromosomes

http://news.sciencemag.org/biology/2014/12/smoking-erases-y-chromosomes

By Gunjan Sinha
4 December 2014

If cancer, heart disease, and emphysema weren’t bad enough, male smokers may have another thing to worry about: losing their Y chromosomes. Researchers have found that smokers are up to four times more likely to have blood cells with no Y chromosome than nonsmokers. That’s worrisome, they say, because a recent study found an association between Y chromosome loss and a shorter life span, as well as a higher risk of multiple cancers.

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The only factors that correlated with high Y chromosome loss were age and smoking, the team reports online today in Science, with smokers 2.4 to 4.3 times more likely to be missing Y chromosomes in their blood cells than nonsmokers.

“It’s a fascinating observation,” says Charles Swanton, head of translational cancer therapeutics at the London Research Institute. The findings, he says, may explain why men have a slightly increased risk of death from the majority of cancers that, unlike breast or prostate cancer, are not specific to either sex. But the number of cells with abnormal chromosomes increases with age anyway, he notes, so the loss of Y may not be directly contributing to cancer. “It would be important to know the mechanism.”

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Meanwhile, there is some reassuring news for smokers, Forsberg says. Y chromosome damage caused by smoking appears to be reversible and dose-dependent. Previous smokers were no more likely to have Y chromosome loss than those who have never smoked, he notes, so it’s never too late to quit.

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