Washington ? Scientists may have found a way to tell which smokers are at highest risk of developing lung cancer: measuring a telltale genetic change inside their windpipes.

A test based on the research is being developed in hopes of detecting this deadly cancer earlier, when it’s more treatable.

And if the work pans out, the next big question is: Might it even be possible to reverse this genetic chain reaction before it ends in full-blown cancer? The researchers found a tantalizing early hint among a handful of people given an experimental drug.

“They’re heading toward lung cancer, and we can identify them with this genomic test,” said Dr. Avrum Spira of Boston University School of Medicine, who led the research published Wednesday in the journal Science Translational Medicine.