November 11, 2010 — Lung cancer in nonsmokers may be a different disease than lung cancer in cigarette smokers, new research suggests.

Accumulating evidence shows striking differences between lung tumors from patients who smoke and those who never smoked. Lung cancer in nonsmokers is more common among women -- Asian women in particular -- than lung cancer in smokers. And lung cancers in smokers tend to carry one particular mutation while those from nonsmokers tend to carry a different mutation.

Now a small study suggests that the path to getting lung cancer is much longer in nonsmokers than in smokers. Tobacco smokers may be taking a shortcut on this path -- or they may be on another path altogether.

PhD candidate Kelsie L. Thu of the BC Cancer Research Center in Vancouver, Canada, and colleagues analyzed the genetic features of lung cancers from 30 people who never smoked, from 14 former smokers, and from 39 current smokers.

They confirmed that while there were similarities, lung tumors from nonsmokers had many genetic changes different from the genetic changes seen in smokers.

But Thu and colleagues also found that the nonsmokers' lung cancers had accumulated more genetic changes than did the smokers' lung cancers.

"Lung cancers in never-smokers should be studied as a separate group," Thu says in a news release.

Interestingly, lung tumors from people who had quit smoking more closely resembled the tumors from nonsmokers than the tumors from smokers.

Thu reported the findings in a presentation to the American Association for Cancer Research's Frontiers in Cancer Prevention Research Conference, held Nov. 7-10 in Philadelphia.


American Association for Cancer Research Frontiers in Cancer Prevention Research Conference, Philadelphia, Nov. 7-10, 2010.

News release, AACR.


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