Clue to lung cancer detected

Boston University researchers have identified a biochemical pathway in cells lining the airways of smokers whose activity rises before lung cancer develops, making it a potential target for an early detection test and possible treatment.

Writing in today's ScienceTranslational Medicine, Dr. Avrum Spira and his colleagues from the  BU School of Medicine and the University of Utah say they had already shown that a particular sequence of genetic activity, called the PI3K pathway, is heightened in patients with lung cancer. Their new findings suggest that this activity precedes tumor formation.

Lung cancer, which is the most common fatal cancer, is usually diagnosed in its later stages when treatment is less effective. Scientists have been searching for a way to determine who among the 10 to 20 percent of smokers and former smokers will go on to develop lung cancer so they can perhaps be followed more closely and their cancers caught earlier.

Spira's team analyzed cell samples taken from 200 patients in Boston and Salt Lake City who were being evaluated for lung disease. People who had higher levels of PI3K activity were more likely to be diagnosed with lung cancer than people with normal levels.

In another part of the study, an experimental drug tamped down the activity of PI3K in precancerous cells of 16 smokers that had been cultured in laboratory dishes.

"We think we've identified a gene activity signature in the airway that can identify smokers who are at risk for getting lung cancer. In addition, we think that the activity in this pathway can serve as a potential therapeutic target," Spira said in an interview.

Spira is a founder, board director, and scientific adviser of Allegro Diagnostics of Boston, which is beginning a larger study of a test based on the research. The study was funded by the National Institutes of Health.

"It's an interesting and potentially important finding, but it's still a long way from being clear what its clinical application will end up being. These things need to be replicated," Dr. Michael Thun, emeritus vice president of epidemiology at the American Cancer Society, said. He was not involved in the study. "There needs to be a more thorough characterization of how consistently it is seen in different types of lung cancer. It is far from the total picture of  the heterogeneity of lung cancer."