Narrator:
An international research team led by M. D. Anderson Cancer Center's
Department of Epidemiology has found two specific genetic variations
that significantly increase the risk of non-small cell lung cancer in
current and former smokers. Study lead author Christopher Amos, Ph.D.,
says this discovery, published in the current issue of Nature Genetics,
advances the search for genetic markers related to lung cancer, the
leading cause of cancer deaths among Americans.
Dr. Amos:
This is the first study that’s identified a common genetic variant that influences the risk for developing lung cancer.
Narrator:
The team includes cancer researchers from England and Texas. Amos says
that up to half the population has at least one version of the two
genetic “snips”, or places in the human genome that vary by a single
DNA chemical building block.
Researchers looked at 317,498 snips in 8,709 Caucasians in Texas and the United Kingdom. Individuals who have ever smoked and who have one or two copies of either of the two snips have increased risks of lung cancer in a range of 28 to 81 percent.
Dr. Amos:
The main risk factor for developing lung cancer is smoking. What we
don’t really know well enough are the specific components of tobacco
smoke that cause lung cancer. There are so many different compounds,
that it’s hard to separate them and we don’t fully understand the
mechanisms given that you’re exposed to tobacco smoke that cause lung
cancer. So if we can identify genetic factors, then we can get a better
handle on how those genetic factors increase risk and what pathways are
involved.
Narrator:
The two snips were found in a region of chromosome 15. There are five
genes in that area, and the researchers’ next job is to track down
which are affected by the genetic snips. Three of those genes are
nicotine receptor genes. Amos says that raises the possibility that
nicotine, whose addictive properties are well-known, might also be
involved in the birth and growth of cancer.
Dr. Amos:
It also raises the point that it’s likely that nicotine itself may play
a role, or at least it raises a question about that, because these
genes have to do with cell growth. The nicotine acetylcholine receptor
genes have to do with cell growth following nicotine exposure.
Narrator:
Amos says the research team will be testing its results in lung cancer
and normal tissue cells, as well as expanding the study to include
African-Americans and people who have never smoked.
Research was funded by the National Cancer Institute, and tapped an ongoing study of M. D. Anderson lung cancer patients that’s been active since 1991.
Dr. Amos:
We are very indebted to the patients that have participated in the
study. There’s no immediate benefit to them, but their help has been
invaluable and being able to do this analysis and should be useful to
future individuals who develop lung cancer.
Narrator:
For more information on this topic, visit mdanderson.org/newsroom.
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