An international group of scientists has identified three genetic
regions that predispose Asian women who have never smoked to lung cancer.
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 second-hand
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.
The article can be found
at: Lan Qin et al. (2012) Genome-wide
association analysis identifies new lung cancer susceptibility loci in
never-smoking women in Asia.
Source: NIH
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