AsianScientist (Nov. 15, 2012) – An international group of scientists has identified three genetic regions that predispose Asian women who have never smoked to lung cancer.
The finding provides further evidence that risk of lung cancer among never-smokers, especially Asian women, may be associated with certain unique inherited genetic characteristics that distinguishes it from lung cancer in smokers.
The majority of lung cancers diagnosed historically among women in Eastern Asia have been in women who never smoked, and the specific genetic variations found in this study had not been associated with lung cancer risk in other populations.
Although environmental factors such as secondhand smoke (also known as environmental tobacco smoke) or exhaust from indoor cooking are likely account for some cases of lung cancer among never-smokers, they explain only a small proportion of the disease.
To gain a better understanding of lung cancer in Asian female never-smokers, researchers from the National Cancer Institute (NCI) in Bethesda, U.S. partnered with researchers from several countries in Asia (China, South Korea, Japan, Singapore) to create the Female Lung Cancer Consortium in Asia.
The consortium conducted one of the largest genome-wide association studies (GWAS) in female never-smokers to date. GWAS compares DNA markers across the genome between people with a disease or trait to people without the disease or trait.
“This study is the first large-scale genome-wide association study of lung cancer among never-smoking females anywhere in the world,” said study leader Dr. Qing Lan, a senior investigator in NCI’s Division of Cancer Epidemiology and Genetics.
The consortium, whose findings were reported online in the journal Nature Genetics, conducted a GWAS that combined data from 14 studies that included a total of approximately 14,000 Asian women (6,600 with lung cancer and 7,500 without lung cancer). The studies included data on environmental factors, including exposure to secondhand smoke.
The consortium found that variations at three locations in the genome — two on chromosome 6 and one on chromosome 10 — were associated with lung cancer in Asian female never-smokers. The discovery on chromosome 10 was particularly significant because it has not been found in any other GWAS of lung cancer in white or Asian populations.
“Our study provides strong evidence that common inherited genetic variants contribute to an increased risk of lung cancer among Asian women who have never smoked,” said senior investigator Dr. Nathaniel Rothman.
The researchers did not detect an association with variations at a location on chromosome 15 that has been associated with lung cancer risk in many previous GWAS of lung cancer in smokers. The absence of this association provides further support for the suggestion that the genetic variation on chromosome 15 may be smoking-related.
In addition, they found that Asian women with one of the newly identified genetic variants may be more susceptible to the effects of environmental tobacco smoke. However, more work is needed to draw definitive conclusions from this observation, they say.
Source: NIH; Photo: mendhak/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
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