Y chromosome linked to cancer: chromosome loss in blood cells may cut men's life span.
Losing the Y chromosome in blood cells may bring on cancer and shorten men's lives, new research suggests. By age 70, about 15 percent of men have lost the Y chromosome from a proportion of their blood cells, statistician and bioinformaticist Lars Forsberg of Uppsala University in Sweden reported October 21.
Forsberg and his colleagues made the discovery by examining the DNA of more than 6,000 middle-aged and elderly Swedish men.
In June, Forsberg's team reported linking Y chromosome loss to a higher risk of several types of cancer and a decreased life span in a smaller group of men. Men who have lost the Y chromosome in at least 10 percent of their blood cells have an average life expectancy of 5.5 years, while men who keep their Y's live around twice as long. The older a man gets, the more of his blood cells lack a Y chromosome, the researchers found.
The loss may weaken immune cells, including white blood cells, making it harder to fight off cancer, Forsberg said.
The researchers think that Y chromo some loss may start sometime around age 40 but doesn't become detectable until 5 to 10 percent of blood cells are missing the chromosome. Y chromosomes are probably lost when cells divide, with some cells failing to divvy up their chromosomes equally. The team is still investigating what might trigger the process in middle age.
A separate study of more than 8,500 men with cancer and more than 5,300 healthy men also found that Y chromosome loss increases with age. About 19 percent of the men were missing the chromosome in some proportion of blood cells by age 80, Stephen Chanock of the National Cancer Institute in Rockville, Md., and colleagues reported October 19. Cigarette smoking may get Y chromosome loss started, the researchers found.
Although Chanock's group found no association with shorter life span, the team did find a link between missing Y chromosomes and certain cancers.
"They've discovered a correlation that replicates, so it's probably not a fluke," said Michael Province, a statistical geneticist at Washington University in St. Louis, noting that the two research teams independently discovered the correlation in different groups of men.
But that doesn't necessarily mean that losing the Y chromosome causes cancer, he stressed. "We just know that they're cohappening." Different types of studies are needed to find the nature of the relationship between Y chromosome loss and cancer, Province said.
Even if losing the Y chromosome doesn't cause cancer, the event might signal that a man is at risk, said Forsberg. Men missing Y chromosomes in blood cells should probably receive more frequent cancer screening, he suggested.
Caption: Loss of the Y chromosome (illustrated in blue next to an X chromosome) in men's blood cells is associated with a high risk of cancer.
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|Title Annotation:||GENES & CELLS|
|Author:||Saey, Tina Hesman|
|Date:||Nov 29, 2014|
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