Researchers in Canada found that the genomes of lung cancer tumors in smokers had different DNA alterations to lung tumors in never smokers, suggesting that the disease could be different in the two groups.
These were the findings of a pilot study presented on Monday at the 9th Annual American Association for Cancer Research (AACR) Frontiers in Cancer Prevention Research Conference that is taking place from 7 to 10 November in Philadelphia, Pennsylvania, USA.
Kelsie Thu, who is working towards a PhD at the BC Cancer Research Center in Vancouver, Canada, and her colleagues concluded that based on their findings, lung cancer in people who have never smoked could be a different disease to lung cancer in people who currently smoke or used to, and should be studied separately.
Thu said in a media statement that:
“A better understanding of the biology underlying lung cancer development will lead to improved detection and therapeutic strategies, and ultimately, will result in improved patient prognosis.”
For the study, Thu and colleagues used genomic technologies to look at the biology and DNA of lung cancer tumors and healthy tissue from 30 patients who had never smoked and 53 patients who were current smokers (39) or used to smoke (14).
They found regions of DNA that showed mutations in both groups, such as those that code for epidermal growth factor receptor (EGFR), which is typical, but the never-smoker tumors genomes contained twice as many DNA alterations overall.
Thu said there are also other differences between never-smokers and smokers with lung cancer. Never-smokers who get lung cancer are usually women, and typically have adenocarcinomas, and more mutations in the EGFR genes.
“Hopefully, our findings will stimulate the research community to further investigate the differences between lung cancer in these two cohorts, which could ultimately lead to the discovery of novel molecular targets for the diagnosis and treatment of lung cancer in never-smokers,” she added.
She said she and her colleagues think the discovery suggests that the never-smoker tumors could be more genomically unstable, and may therefore develop through different molecular routes.
In another comment to MyHealthNewsDaily, she said perhaps never-smokers are exposed to a carcinogen, not from smoking cigarettes, that causes their tumors to have more DNA mutations and spur the growth of lung cancer.
Previous studies have suggested that lung cancer in smokers and never-smokers has different molecular pathways, but this is the first study to look beyond individual gene changes and find whole regions of DNA alterations.
Thu said they now want to confirm the findings and look at DNA in other lung tumors, sourcing the data from results of other studies. Perhaps they will find the same alterations and can start to work out what functions those DNA regions perform.
Sources: AACR, MyHealthNewsDaily.
Written by: Catharine Paddock, PhD