London, Apr 3 : Researchers at Johns Hopkins, as part of a large, multi-institutional study, have identified for the first time genetic variations that increase the risk of lung cancer in people who smoke.
The research team, led by Kimberly Doheny, Ph.D., assistant director of the Center for Inherited Disease Research at the McKusick-Nathans Institute of Genetic Medicine at Johns Hopkins, took DNA from 1,154 smokers suffering from lung cancer and 1,137 smokers without lung cancer.
The researchers examined each DNA sample at above 300,000 points between individuals with cancer and without cancer, in order to find out variations, known as single nucleotide polymorphisms (SNP).
Then the top 10 SNPs in an additional 5,075 DNA samples from smokers with and without lung cancer was also analysed.
The researchers discovered that out of the 10 SNPs, 2 were constantly linked to lung cancer risk. Besides, both the SNPs were located in chromosome 15 inside a region containing genes for the nicotinic acetylcholine receptor alpha subunits 3 and 5, which are already believed to play a role in lung cancer progression.
Later, the researches wanted to know if these genetic associations are also linked to nicotine dependence, and discovered that the same two SNPs also are weakly associated with smoking behaviour.
"The power of genome-wide analysis is to look at many markers and many samples at once, which can reveal weak genetic associations in complex diseases like lung cancer," said Doheny.
The study is published in the latest issue of Nature Genetics.