NEW YORK (Reuters Health) - DNA methylation, a key component of lung cancer initiation and progression, can be reliably detected and analyzed in exhaled breath condensate, according to a pilot study reported Sunday at the 100th annual meeting of the American Association for Cancer Research in Los Angeles.

"DNA modifications correlate fairly tightly with lung cancer," study presenter Dr. Simon D. Spivack noted in a telephone interview with Reuters Health.

"We developed an assay that looks at DNA methylation in exhaled breath condensate and asked: Can we find DNA in exhaled breath and can we apply our DNA methylation mapping technique to it? And the punch line is yes, it is technically feasible."

Dr. Spivack is a research physician in the Human Toxicology and Molecular Epidemiology Laboratory at the New York State Department of Health's Wadsworth Center in Albany.

In a preliminary study of 33 individuals, there were statistically apparent differences in DNA methylation patterns among selected gene promoters in exhaled breath between never-smokers, former and current smokers and those with lung cancer.

"It's clear that we can technically measure markers that are well known to be related to cancer in exhaled breath and they presumably represent lung derived markers for cancer risk -- that's the hope," Dr. Spivack said. "We have to study more people and refine the choice of genes that we look at but there is no question that this is feasible," he added.

Tracking lung carcinogenesis by DNA methylation mapping from exhaled breath could serve as a cost-effective pre-screening tool to spot individuals at high-risk for lung cancer who may benefit from further tests.

"Lung cancer risk can be considered to be modifications to the whole bronchial tree," Dr. Spivack noted. "Therefore, if we can sample broadly that epithelium noninvasively, then we can make inferences about the state of that epithelium including whether someone is at high risk. This information would actually improve the yield and accuracy of other tools, like low-dose CT."