Sensitive to Smoke, Lung Cancer Gene
Medical Authors and Editors: Barbara K. Hecht,
Frederick Hecht, M.D.
July 27, 2004 -- A gene that determines the susceptibility to lung cancer has
been localized to chromosome 6. This is the first
major success in mapping the
genetic vulnerability to lung cancer.
Lung cancer is a leading cause of death in the United States and many other
countries. The risk is greatly increased by cigarette smoking and certain
environmental exposures but genetic factors also clearly play a major role.
A report just posted online in the American Journal of Human Genetics outlines the
discovery. A study was done of families with 3 or more first-degree relatives
who had lung, throat, or laryngeal cancer with a special focus on
those families that had affected relatives in at least 2 generations.
A battery of almost 400 genetic markers were examined in
all available family
members. The markers were DNA sequences known to be polymorphic, often variable.
The lung cancer susceptibility gene was found linked to a genetic marker on chromosome 6 with a high
degree of certainty. The genetic marker is on the long (q) arm of chromosome 6.
The lung cancer region on 6q is quite large. It runs from chromosome band 6q23 through band 6q25. (Chromosome bands are so big that they can be
seen under an ordinary microscope.) The region contains about 20 million base pairs, 20
million letters (A, T, G, or C) in the DNA.
To identify the gene itself responsible for lung cancer
susceptibility is like looking for the proverbial needle in the haystack.
However, this search may be sped up by first scrutinizing the most likely
suspects, or candidate genes, Among them are several possible tumor suppressor genes known to be lurking in
Ultrasensitive to Smoke
People carrying the familial lung
cancer gene appear unusually sensitive to tobacco smoke Even a small amount of
smoking may be enough to cause lung cancer. (By contrast, the risk of lung cancer rises with the amount of smoking in people
who do not carry this gene.)
This is a major discovery. We expect that the gene will soon be identified
and sequenced. That will end the first chapter in the book on the genetics of
lung cancer susceptibility.
JE Bailey-Wilson and others. A Major Lung Cancer
Susceptibility Locus Maps to Chromosome 6q2325. Am. J. Hum. Genet., 75:000, 2004
Last Editorial Review: 7/27/2004