Lung cancer appears to run in families, researchers said on Tuesday, though exposure to tobacco smoke is still the dominant cause of the disease even for those who may be genetically predisposed. The strongest family link was found in the relatives of patients who developed the disease at age 60 or younger. The parents of such people had nearly a three and one-half times higher risk of also developing the disease compared to the general population, the study said. For siblings in such cases the risk was more than three times higher and for children slightly less than that. The genetic risk also extends beyond the immediate family, said the report from Landspitali-University Hospital in Reykjavik, Iceland. Aunts and uncles, cousins, nieces and nephews of lung cancer victims of any age also run a higher risk, though at lower levels than the immediate family. Lung cancer is the leading cause of cancer deaths among men and women in many Western countries, said the study, published in this week’s Journal of the American Medical Association, and smokers comprise about 90 percent of all cases. The Icelandic researchers said they traced the genetic links by looking at all 2,756 patients diagnosed with lung cancer in the country from 1955 to 2002 and linking them with an extensive genealogical database containing all living Icelanders and most of their ancestors since the settlement of the country.
