Scientists Find Genes Responsible for Lung Cancer

An international research team has recognized two genetic variations that seem to boost a person's risk of developing lung cancer by up to sixty percent. Lung cancer is the top cause of cancer death in men and the second leading cause of cancer death among women worldwide, according to the American Cancer Society, with about 975,000 men and 376,000 women forecast to die annually. Smoking is the leading risk factor, but increasingly scientists are looking to genetics to help explain why some long-time smokers never develop the disease and why some non-smokers do.

Genetic mutations in more than 15,000 people - 6,000 with lung cancer and 9,000 without the disease were analyzed. "We are looking at differences in the DNA that makes you more or less likely to develop lung cancer," said Paul Brennan, a cancer epidemiologist at the World Health Organization's International Agency for Research on Cancer. "The idea is if you can recognize genes then that might be a sign of lung cancer." The researchers discovered a region on the fifth chromosome containing two genes - TERT and CRR9 - where variations can increase the likelihood of lung cancer by as much as sixty percent. "Not much is known about CRR9, but the TERT gene research is promising, because it makes active an enzyme called telomerase, which is key to aging and cancer", Brennan said.

Cancer is caused by defects in DNA, the basic genetic material. All chromosomes, which carry the DNA, also have little caps on each end called telomeres. Each time a cell divides; these telomeres become a little more frayed. When they are too worn out, the cell dies. However, when cells become cancerous, they produce telomerase, which can renew the telomeres and lets the cells reproduce out of control, eventually to form a tumor. So implicating the TERT gene in a specific cancer can help lead to a better understanding of how cancer develops and increase the invention of new drugs to stop tumors, Brennan added. "The principle is there," he said - "if one can identify what goes wrong, it may be possible to recognize targeted drugs."