Familial lung cancer: Lung cancer that recurs in families. Lung cancer can occur sporadically in people with no known family history of lung cancer or it can occur in two or more members of the same family and constitute familial lung cancer.
A gene for familial lung cancer is on the long (q) arm of chromosome 6 in a region that runs from chromosome band 6q23 through band 6q25. People carrying this gene for familial lung cancer appear unusually sensitive to tobacco smoke. Even a small amount of smoking may be enough to cause lung cancer. By contrast, the risk of lung cancer rises with the amount of smoking in people who do not carry this gene.