The mutation strikes women smokers three times more often than men, the researchers found. The findings suggest that this mutation, known as K-ras, helps the tumor proliferate in response to the body's natural growth hormones, particularly estrogen in women, they conclude. The sobering report, by scientists at Harvard University and the University of California, San Francisco appears in the December issue of the Journal of the National Cancer Institute. Incidence of adenocarcinoma is on the rise and is more common in women than men, they noted. While the K-ras mutation is found in about 10 percent of all lung cancers, it is detected in about one fourth of adenocarcinomas, and almost exclusively among smokers, Wiencke said.
Lung cancer is the leading cause of cancer death, both in the U.S. and worldwide.
First author on the scientific paper is Heather H. Nelson, PhD, research associate in cancer cell biology at the Harvard School of Public Health. The scientists studied patients who were about to undergo surgery for non-small cell adenocarcinoma. They found the K-ras mutation only among the lung cancer patients who had been smokers, yet those who had smoked relatively lightly or briefly and then quit were just as prone to the mutation as those who smoked for many years. The pattern, Wiencke said, highlights the importance of avoiding smoking in the first place. This finding applies only to this type of cancer, he stressed, and quitting has definitely been shown to decrease the likelihood or severity of other serious illnesses such as heart disease and emphysema.