Lung Cancer Risk Mapped in Genomes of Nonsmokers

Chest radiograph showing a cancerous tumor in the left lung.

About 10 percent of lung cancer cases involve people who have never smoked, but this group of patients has never received as much study as smokers. Now, HealthDay News reports that scientists from the Translational Genomics Research Institute in Phoenix have begun mapping the genomes in non-smokers to get the ball rolling on new treatments for the disease.

Led by senior postdoctoral fellow Timothy Whitsett, the team is conducting genetic analyses on three female patients with adenocarcinoma of the lung. One woman is a never-smoker with early-stage cancer, one is a never-smoker with late-stage cancer, and one is a smoker with early-stage cancer. By identifying the genes and pathways associated with lung cancer, the team hopes to find some commonalities and differences between smokers and non-smokers that could lead to better treatment.

Whitsett said he and his colleagues have already found some observable differences.

“In the never-smoker with early-stage cancer, there were very few mutations in the genome, but when we looked at the whole transcriptome, we saw difference in gene expression,” he said in a news release.

He also noted that the never-smoker with late-stage cancer had mutations in the “classic tumor-suppressor genes,” leading researchers to believe that these mutations could be a factor in late-stage lung cancer in people who have never smoked.

HealthDay reported that both never-smokers also lacked mutations in the genes commonly associated with lung cancer, such as EGFR, KRAS and EML/ALK. This suggests that other, undiscovered mutations are at work in non-smokers who develop lung cancer. From here, Whitsett and his team plan to look at an even larger sample of never-smokers and smokers with lung adenocarcinoma. “This is the starting point,” he said. “We certainly have a lot of pathways and gene expression alterations that we’re going to be very interested in confirming and looking at in larger cohorts of patients.”
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