The variant, which is found in a region of DNA that encodes parts of the nicotine receptors, is thought to increase smoker’s chance of contracting lung cancer by 30% if they inherit one copy of the variant and by 80% if two copies of the variant are inherited. According to Paul Brennan, a geneticist at the International Agency for Research on Cancer in Lyon, this means that a smoker with 2 copies of the variant has a 1 in 4 chance of developing lung cancer.
The variant which is carried by about half of people with European ancestry may not only sensitise a person’s cells to nicotine but make it harder for them to quit. Furthermore it if you start smoking and you have the variant you will smoke a lot more than the rest of the population on average. According to Kari Stefansson, CEO of deCode Genetics in Reykjavik, Iceland, the variant is also a causal force behind peripheral arterial disease, another common disease among smokers.
Despite the startling evidence, not everyone involved is decided on what underlies the link. Brennan himself believes that addiction alone cannot explain the increasing odds of cancer. Doug Easton at the University of Cambridge adds that perhaps studying people who have the variant but have never smoked might hold the answer. Either way, researchers are now keen to use the newly discovered link to help fight lung cancer and potentially combat tumours.
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Picture from: http://www.abc.net.au/news/stories/2008/01/09/2134636.htm
Published by: Isaac Halloran 41767155