In the news
Find related articles on
Genetic link for smoking and lung cancer
Lung cancer is the most common cause of cancer death worldwide. It is also the most preventable, since, according to the World Health Organisation, smoking causes around 90% of all cases. Assessing the impact of genetic variants on smoking-related diseases is important for public health and understanding gene-environment interactions.
A massive genome-wide association study published in the journal Nature has identified a gene variant associated with nicotine dependence, lung cancer and peripheral arterial disease [Thorgeirsson et al. (2008) Nature 452:638]. The paper is published back-to-back with another independent study focussing on lung cancer patients, which identified almost the same risk locus [Hung et al. (2008) Nature 452:633]. Another genome-wide analysis with a similar finding is simultaneously published in the journal Nature Genetics [Amos et al. (2008) Nat. Genet. :10.1038/ng.109:10.1038/ng.109].
The biggest study, run by the Icelandic company deCODE genetics, involved nearly 11,000 smokers in Iceland and 32,000 lung cancer patients and controls from around the world. By testing over 300,000 single nucleotide polymorphisms (SNPs), they were able to identify a common variant present in around half the population associated with lung cancer and peripheral arterial disease. The risk variant is located within the nicotinic acetylcholine receptor gene cluster on chromosome 15q24-25, which plays an important role in neurotransmission. Each copy of this SNP confers approximately a 30-40% increase in risk of lung cancer and a 20% increase in risk of peripheral arterial. The risk variant was also found to be associated with the number of cigarettes smoked per day, suggesting a link to nicotine dependence.
A typical smoker with two copies of this risk variant has a 1 in 4 lifetime risk of developing lung cancer; in contrast, a non-smoker (who has smoked fewer than 100 cigarettes) has less than a 1% chance of developing the disease (see news in Nature and New Scientist). The strength of the association comes from the enormous power of the combined studies, which involved over 50,000 people, and their independent replication of the same risk locus with a relatively large effect size. According to their website, the company’s personal genome profile service, deCODEme, will offer the test for this gene variant immediately. However, cancer campaigners stress that smoking is still by far the number-one risk factor for lung cancer.
Comments (2)
jems (December 7 2009, 4:43 am)
Lung cancer is a disease of uncontrolled cell growth in tissues of the lung. This growth may lead to metastasis, which is the invasion of adjacent tissue and infiltration beyond the lungs.Lung cancer is directly related to smoking. Over 40 carcinogens have been identified in cigarette smoke. The risk of developing lung cancer is directly related to the number of cigarettes smoked. The change in consumption from unfiltered high tar cigarettes to filtered low tar cigarettes parallels the change in incidence from squamous cell carcinoma to adenocarcinoma. There is a long interval between quitting smoking and elimination of lung cancer risk. Up to 40% of newly diagnosed lung cancer occurs in former smokers. Mio Navman M350D
vidya (October 29 2009, 12:34 pm)
To put it simply, these genetic changes upset the normal process of protein production. This ultimately results in the production of protein that is so small in amount that it becomes practically non-functional.
http://www.jacobintl.org/
http://www.jacobintl.org/