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Genes Hold the Key to Smoking Addiction

Posted on: Wednesday, 2 April 2008, 15:20 CDT

Scientists believe they have successfully pinpointed a genetic link that can increase risks of smoking addiction and lung cancer in smokers.

Three studies conducted by researchers in France, Iceland and the U.S. reported locating two key areas of variation on chromosome 15 that raise lung cancer risk by 70-80 percent in people who have smoked.

People who have only one copy of each variant have a raised risk of about 28 percent.

Each research team studied thousands of smokers, ex-smokers and nonsmokers.

"This is really telling us that the vulnerability to smoking and how much you smoke is clearly biologically based," said psychiatry professor Dr. Laura Bierut, of Washington University in St. Louis, and a genetics and smoking expert who did not take part in the studies.

Most remarkably, all three separate teams were able to spot variants in the same area of chromosome 15 that hosts three nicotine receptor genes.

"It opens the possibility that treatments that block these genes could be very beneficial as a treatment strategy against lung cancer, as well as against addiction," Paul Brennan of the International Agency for Research on Cancer in Lyon, France, told reporters.

Icelandic company deCODE Genetics said its team collected enough evidence to indicate that carriers of the variants are more susceptible to nicotine addiction.

However, an international team of researchers said it is more likely that the variants interact directly with tobacco to cause lung cancer.

“These findings provide an example of the power of human genetics for shedding light on the most complex health challenges,” said Kari Stefansson, CEO of deCODE.

“Not only have we made a convincing link between a single SNP and a behavioral disorder - greater smoking quantity and addiction to nicotine - but also demonstrated how this risk factor translates into risk of lung cancer and PAD.”

Researchers added that personalized testing could reduce the effect of public health messages against smoking . Even if someone is somewhat genetically resistant to lung cancer, they are still susceptible to heart disease and respiratory disorders, they said.

They also found that smokers who do not have the variants are still more than 10 times more likely to get lung cancer than people who have never smoked, whose risk is less than 1 percent.

This is not first study to find relationships between genetic variations and diseases. Since 2007, variations have been linked to diabetes, heart disease and various cancers.

"It's very likely that in the end there's going to be a test and this is going to be folded into a panel of tests for the risk of cancers," said Stefansson, whose company already does prostate cancer genetic tests. The tests will lead to better treatments, but probably not prevention of smoking, he said.

All three groups published their findings in journals Nature and Nature Genetics.

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On the Net:

deCODE Genetics

Nature

Nature Genetics

Source: redOrbit Staff and Wire Reports

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