Why Never-Smokers Get Lung Cancer

Lung cancer in never smokers produces specific genetic changes

(RxWiki News) While the incidence of lung cancer is decreasing in this country, there's another alarming trend. Roughly one in 10 individuals who is diagnosed with lung cancer has never smoked! And researchers are trying to understand why.

Scientists have identified genetic mutations in never-smokers with lung cancer. These findings could open the door for developing ways to target these aberrations as a means of fighting the disease.

"If you experience hoarseness or difficulty breathing, talk to your doctor right away."

"Looking at the genetic background in never-smokers is very relevant because the incidence of lung cancer is increasing in this group and we don't know why," Fred R. Hirsch, M.D., Ph.D. professor of medicine and pathology at the University of Colorado Cancer Center," told dailyRx in a telephone interview.

Never-smokers are people who have smoked fewer than 100 cigarettes in their entire lives. This population of lung cancer patients has not been largely studied, until now.

In a study directed by Timothy G. Whitsett, Ph.D., senior postdoctoral fellow in the cancer and cell biology division at the Translational Genomics Research Institute (TGen), researchers looked at genetic changes in three female lung cancer patients - a never-smoker with early disease; a never-smoker with late stage disease and one smoker with early lung cancer.

The team analyzed the genetic make-up of these patients to find any alterations that could lead to either the development of or the advancement of their specific type of lung cancer.

They used advanced technology - whole genome sequencing (WGS) and whole transcriptome sequencing (WTS) - to perform this analysis.

They found few genetic changes in early stage disease in the never-smoker. In the never-smoke with late stage, they found mutations in genes that normally block cancer growth.

Dr. Hirsch explained, "The mutations of gene suppressors in late stage disease could tell us more about the selection of genes involved in advancing the cancer."

Interestingly, the never-smokers did not have genes normally associated with lung cancer. The researchers say this finding suggests that new, yet to be discovered genetic mutations may drive lung cancers in never-smokers.

WGS and WTS open new opportunities to advance the understanding of cancer origins. These technologies have “ 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,”  Whitsett said.

The research team is currently validating its findings in 30 never-smokers with lung adenocarcinoma and about 60 clinically matched smokers with the disease.

Whitsett presented these findings at the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer: Biology, Therapy and Personalized Medicine, held Jan. 8-11, 2012.

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Review Date: 
January 10, 2012