A new study has been conducted by an international team led by researchers at the US National Cancer Institute (NCI), part of the National Institutes of Health (NIH). The findings were published in Nature Genetics, describing three molecular subtypes of lung cancer in people who have never smoked. The analysis done in people with no history of smoking has found that majority of tumors arise from accumulation of mutations caused by natural processes.
In this study; the researchers used whole-genome sequencing to find the genomic changes in tumor tissues and then matched normal tissue with 232 never smokers. The tumors included 189 adenocarcinomas, 36 carcinoids and 7 other tumors of different types. These never smokers had been diagnosed with non-small cell lung cancer but had not yet undergone any treatment. The researchers combed the tumor genomes for mutational signatures like damage from natural activities in the body. The team has discovered that majority of tumor genomes of these lung cancer patients bore mutational signatures associated with damage from endogenous processes.
‘We’re at the beginning of understanding how these tumors evolve,’ Dr Maria Teresa Landi said. ‘This analysis shows that there is heterogeneity, or diversity, in lung cancers in never smokers.’ The study was limited to only those people who are non smokers and thus, the researchers did not find any mutational signatures that have previously been associated with direct exposure to smoking. Also, they did not find those signatures among 62 patients who had been exposed to second-hand tobacco smoke.
Considering the limitations of the study, more research is required to be done to classify different lung cancer subtypes and then develop treatments for those who have never smoked.
The information shared in this blog is for educational purposes only and is certainly not a substitute for medical advice. It is advised to consult your healthcare practitioner for any health issues.