Jennifer Mathews: More than 170,000 Americans are diagnosed with lung cancer each year and 160,000 will die from the disease.

Dr. Peter Mazzone: That makes lung cancer far and away the most common cause of cancer-related death in the United States. .

Jennifer Mathews: Dr. Mazzone says, "The disease is difficult to diagnose early because there are no symptoms."

Dr. Peter Mazzone: It would be wonderful if we could pick it up as early as possible when it's more easily treated and potentially cured.

Jennifer Mathews: One day that may be possible with this. A machine that actually sniffs out lung cancer, you simply breathe into the mouthpiece for about 12 minutes.

Dr. Tarek Mekhail: It's a nose. It's an electronic nose.

Jennifer Mathews: That nose detects chemical changes in the breath that signal cancer.

Dr. Tarek Mekhail: Individuals with bone marrow cancer would have abnormal blood. Individual with bladder cancer or kidney cancer would have abnormal urine. So we think that individuals with lung cancer also have abnormal breath.

Jennifer Mathews: A recent study showed an earlier version of the electronic nose was about 75% successful at detecting lung cancer.

Roman Wlaszyn already knows he has lung cancer. But he's participating in a new phase of the study to see if the machine can make an accurate diagnosis.

Roman Wlaszyn: If they can pick up on any kind of markers to find them sooner, it's obviously better.

Jennifer Mathews: Researchers hope one day the breath test will screen everyone, catching cancer in its earliest stages.

This is Jennifer Mathews reporting.