People who smoke even a little have a dramatically increased risk of lung cancer if they carry a rare version of a small piece of chromosome 6.
A handful of genes have been found that can slightly alter the risk of lung cancer, but a few studies have suggested that rare mutations in some genes could boost the risk of the cancer 14 times.
After a 20-year hunt, human geneticist Joan Bailey-Wilson at the National Human Genome Research Institute near Washington DC and her colleagues believe they have narrowed down the search for one or more of these 鈥渕ajor lung cancer susceptibility genes鈥� to a piece of chromosome 6 containing about 50 human genes (American Journal of Human Genetics, vol 75, p 460). 鈥淲e consider 10 of these genes hot prospects,鈥� she says. The suspects include known tumour-suppressor genes. Mutations in these genes could allow lung cancers to grow unhindered.
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Once the genes themselves have been identified, researchers will be able to work out exactly how much they increase the risk of lung cancer and use them to screen for high-risk individuals. 鈥淚f you knew you were at higher risk, that might be a strong motivating force to not start smoking or to stop,鈥� says Bailey-Wilson. But she says the biggest pay-off will be new insights into how lung cancers form.