Cancer-Causing Mutation Strikes Women Smokers at Three Times the Rate of Men
For immediate release: November 30, 1999
Boston, MA--Researchers from the Harvard School of Public Health (HSPH) have discovered that smoking seems to be a prerequisite for a particularly harmful form of lung cancer and that women are three times more likely than men to have this cancer.
This cancer, caused by a cell mutation known as K-ras, is aggressive in early stages of lung cancer. Patients who received surgery for lung cancer in its early stages and who had this mutation were four times more likely to die than those without the mutation.
The scientists studied patients who were about to undergo surgery for non-small cell adenocarcinoma. They found the K-ras mutation only among lung cancer patients who had been smokers. "Unfortunately," said Heather Nelson, lead researcher, "among lung cancer patients, smokers who had quit smoking or who were light smokers were just as likely to have the K-ras mutation as were heavy smokers. The carcinogens in tobacco seem to have their effect on the cells very early in the evolution of lung cancer."
"We also found that women are three times more likely than men to have the K-ras mutation," said Nelson, "suggesting that there may be a relationship between estrogen and the mutation."
This work has profound implications for the treatment of lung cancer. The most common treatment for patients who have been diagnosed early in their cancer is surgery, with radiation therapy and/or chemotherapy reserved for those in later stages of the disease. Because of the particularly deadly effect of the K-ras mutation, said Nelson, "patients who receive surgery could be tested for the mutation. If found, the patients may benefit from undergoing the more aggressive radiation therapy immediately."
Lung cancer is the leading cause of cancer death in the US. There are 180,000 new cases of lung cancer diagnosed each year. The K-ras mutation is found in about 10 percent of lung cancers.
The research is published in the December, 1999, issue of the Journal of the National Cancer Institute as "Implications and Prognostic Value of K-ras Mutation in Early Stage Lung Cancer in Women." Coauthors include other researchers from HSPH, as well as from Massachusetts General Hospital and University of California at San Francisco.
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