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Double-whammy gene says ‘don't light up’
This week– OLIVER CULMANN/TENDANCE FLOUE
SOUNDBITES ‹ How does it feel to be a pregnant man? Incredible. Despite the fact that my belly is growing, I am stable and confident being the man that I am.› Thomas Beatie, who describes himself as a transgender male, claims in a magazine article that he is five months pregnant. He kept his reproductive organs after his sex-change operation (The Advocate, Los Angeles, 25 March)
–Who’s at greatest risk?–
The gene that tells you ‘don’t light up’ Agency for Research on Cancer in Lyon, France, who led another of THINK tobacco is a danger to your the teams. Inheriting two copies of the variant increases the risk by health? It could be even worse if 80 per cent. A smoker with two you possess a genetic mutation copies has a 1 in 4 chance of linked to a dramatic increase in developing lung cancer, he says. smokers’ already high odds of The other studies reached developing lung cancer. “It’s sort of a double whammy,” similar conclusions, but the says Christopher Amos, a geneticist researchers disagree on how the increased risk arises. at the M. D. Anderson Cancer “If you start smoking and you Center in Houston, Texas, who led one of three teams to discover the have this variant, you’re going to gene variant. The variant, which is smoke more, much more, than the rest of the population,” says carried by around half of people with European ancestry, may not only sensitise cells to nicotine, but “If you start smoking and you also make it harder for smokers to have this variant, you’re going kick their habit. to smoke much more than the Previous studies have hinted rest of the population” that genes play a role in lung cancer, but none as strikingly as the new reports in Nature (vol 452, Kari Stefansson, CEO of deCode Genetics in Reykjavik, Iceland, p 633 and p 638) and Nature which carried out the third study. Genetics (DOI: 10.1038/ng.109). This will clearly increase your risk Smokers with one copy of the of lung cancer. The mutation is variant, which is in a region of also linked to an increased DNA known to encode parts of incidence of peripheral arterial the nicotine receptor, are 30 per disease, a condition common cent more likely to develop lung among smokers. cancer than those without, However, Brennan believes according to Paul Brennan, a that addiction alone cannot geneticist at the International EWEN CALLAWAY
10 | NewScientist | 5 April 2008
explain the increased odds of cancer. “The gene does have an addiction effect, but it’s too modest to explain the increase,” he says. Instead, he thinks the gene variant may directly increase a person’s risk of cancer, by influencing a cell’s response to nicotine or its metabolites, for example. Previous studies have suggested that a metabolite of nicotine could stimulate cell division via the same receptor. Brennan’s team found no link between the mutation and other cancers caused by smoking, such as head and neck cancers. Others are undecided about what underlies the link. “I think the jury’s out,” says Laura Bierut, a geneticist at Washington University in St Louis, Missouri, who has previously linked the gene variant to smoking addiction. Studying the incidence of lung cancer in people with the variant who have never smoked might provide a clearer answer, adds Doug Easton at the University of Cambridge. Researchers are now eager to use the newly discovered link to fight lung cancer. If the mutation contributes to lung cancer directly, drugs targeting the nicotine-sensing proteins might combat tumours. If the genes are involved in cigarette addiction, genetic counselling could be used to dissuade people with the mutation from ever lighting up. G
‹ The banks should have embraced this wholeheartedly and they didn’t. But it’s a start.› Cathy Flanagan, one of the organisers of Earth Hour, a timed voluntary blackout in cities all over the world to highlight climate change, lamenting the fact that in her city of Dublin many empty offices left their lights on (Associated Press, 29 March)
‹ They want people to pay for their incompetence and their mistakes.› Frank Silvestri is angry that he and many others affected by hurricane Katrina are now being chased for money by a private contractor, ICF International, after it overpaid them in federal grants to repair their homes – in some cases by as much as $150,000 (Associated Press, 29 March)
‹ It is a classic example of a short-term fix now unravelling.› Tim Lang of the UK Sustainable Development Commission, who is not celebrating the 75th anniversary of the invention of the plastic bag (The Independent, London, 26 March)
‹ It’s only about 20 kilograms, which is half a bag of dog biscuits or whatever.› Australian outback farmer James Stirton has asked NASA to help identify a mangled piece of metal he found on his ranch. He thinks it might be a chunk of fallen satellite (ABC News, 31 March)
www.newscientist.com
SOUNDBITES ‹ How does it feel to be a pregnant man? Incredible. Despite the fact that my belly is growing, I am stable and confident being the man that I am.› Thomas Beatie, who describes himself as a transgender male, claims in a magazine article that he is five months pregnant. He kept his reproductive organs after his sex-change operation (The Advocate, Los Angeles, 25 March)
–Who’s at greatest risk?–
The gene that tells you ‘don’t light up’ Agency for Research on Cancer in Lyon, France, who led another of THINK tobacco is a danger to your the teams. Inheriting two copies of the variant increases the risk by health? It could be even worse if 80 per cent. A smoker with two you possess a genetic mutation copies has a 1 in 4 chance of linked to a dramatic increase in developing lung cancer, he says. smokers’ already high odds of The other studies reached developing lung cancer. “It’s sort of a double whammy,” similar conclusions, but the says Christopher Amos, a geneticist researchers disagree on how the increased risk arises. at the M. D. Anderson Cancer “If you start smoking and you Center in Houston, Texas, who led one of three teams to discover the have this variant, you’re going to gene variant. The variant, which is smoke more, much more, than the rest of the population,” says carried by around half of people with European ancestry, may not only sensitise cells to nicotine, but “If you start smoking and you also make it harder for smokers to have this variant, you’re going kick their habit. to smoke much more than the Previous studies have hinted rest of the population” that genes play a role in lung cancer, but none as strikingly as the new reports in Nature (vol 452, Kari Stefansson, CEO of deCode Genetics in Reykjavik, Iceland, p 633 and p 638) and Nature which carried out the third study. Genetics (DOI: 10.1038/ng.109). This will clearly increase your risk Smokers with one copy of the of lung cancer. The mutation is variant, which is in a region of also linked to an increased DNA known to encode parts of incidence of peripheral arterial the nicotine receptor, are 30 per disease, a condition common cent more likely to develop lung among smokers. cancer than those without, However, Brennan believes according to Paul Brennan, a that addiction alone cannot geneticist at the International EWEN CALLAWAY
10 | NewScientist | 5 April 2008
explain the increased odds of cancer. “The gene does have an addiction effect, but it’s too modest to explain the increase,” he says. Instead, he thinks the gene variant may directly increase a person’s risk of cancer, by influencing a cell’s response to nicotine or its metabolites, for example. Previous studies have suggested that a metabolite of nicotine could stimulate cell division via the same receptor. Brennan’s team found no link between the mutation and other cancers caused by smoking, such as head and neck cancers. Others are undecided about what underlies the link. “I think the jury’s out,” says Laura Bierut, a geneticist at Washington University in St Louis, Missouri, who has previously linked the gene variant to smoking addiction. Studying the incidence of lung cancer in people with the variant who have never smoked might provide a clearer answer, adds Doug Easton at the University of Cambridge. Researchers are now eager to use the newly discovered link to fight lung cancer. If the mutation contributes to lung cancer directly, drugs targeting the nicotine-sensing proteins might combat tumours. If the genes are involved in cigarette addiction, genetic counselling could be used to dissuade people with the mutation from ever lighting up. G
‹ The banks should have embraced this wholeheartedly and they didn’t. But it’s a start.› Cathy Flanagan, one of the organisers of Earth Hour, a timed voluntary blackout in cities all over the world to highlight climate change, lamenting the fact that in her city of Dublin many empty offices left their lights on (Associated Press, 29 March)
‹ They want people to pay for their incompetence and their mistakes.› Frank Silvestri is angry that he and many others affected by hurricane Katrina are now being chased for money by a private contractor, ICF International, after it overpaid them in federal grants to repair their homes – in some cases by as much as $150,000 (Associated Press, 29 March)
‹ It is a classic example of a short-term fix now unravelling.› Tim Lang of the UK Sustainable Development Commission, who is not celebrating the 75th anniversary of the invention of the plastic bag (The Independent, London, 26 March)
‹ It’s only about 20 kilograms, which is half a bag of dog biscuits or whatever.› Australian outback farmer James Stirton has asked NASA to help identify a mangled piece of metal he found on his ranch. He thinks it might be a chunk of fallen satellite (ABC News, 31 March)
www.newscientist.com