Researchers said Monday they have identified some mutations and cellular pathway changes that can lead to lung cancer in people who have never smoked.

The new study marked a significant step in the development of potential therapeutic targets for patients with lung cancer who have never smoked, according to researchers from the Translational Genomics Research Institute said in a released statement.

They sought to identify pathways and genes in patients with lung adenocarcinoma who had never smoked by using parallel DNA and RNA sequencing. They also looked at smokers with early-stage lung cancer to determine gene mutations and pathway alterations that could have led to the development and progression of their specific lung cancer.

"In the never-smoker with early-stage cancer, there are very few mutations in the genome, but when we looked at the whole transcriptome, we see differences in gene expression," said Dr. Timothy Whitsett, Senior Postdoctoral Fellow in at the institute’s Cancer and Cell Biology Division.

Researchers found that never-smokers with late-stage disease had mutations Whitsett called the “classic tumor-suppressor genes” and Whitsett predicted that mutations of this gene might be a factor in late-stage lung cancer in never-smokers.

Researchers also reported that these never-smokers’ tumors did not have alterations in common genes associated with lung cancer, which makes these patients ideal cases for the discovery of new mutations that may drive lung adenocarcinomas in never-smokers.

Whitsett said that using whole genome sequencing and whole transcriptome sequencing to determine cancer origins "has become a way to really dive down into an individual tumor to try to understand the pathways that may be driving that tumor and identify what therapeutic interventions may be possible."

The study was presented on Monday at the American Association for Cancer Research and International Association for the Study of Lung Cancer Joint Conference on Molecular Origins of Lung Cancer: Biology, Therapy and Personalized Medicine in San Diego.