The study was conducted by an international team led by researchers National Cancer Institute (NCI), belonging to national institutions Health (NIH) d United States, Describes three molecular subtypes for the first time Lung cancer In non-smoking people.
It has been found that most of these tumors arise from the accumulation of mutations caused by natural processes in the body. Published by researchers in the journal Nature Genetics.
This insight will help unravel the mystery of how lung cancer arises in people who do not have a history of smoking. And they can guide the development of the most accurate medical treatment.
“What we see is that there are different subtypes Lung cancer Never in smokers with different molecular properties and evolutionary processes. In the future we will be able to get different treatments based on these subtypes, ”explains Maria Theresa Landy, the epidemiologist who led the study.
Development of a study against lung cancer in non-smokers
In this large epidemiological study, the researchers used a complete genetic sequence to classify genetic mutations in tumor tissue and associated normal tissue from 232 non-smokers diagnosed with small cell lung cancer.
Tumors include 189 adenocarcinomas (the most common type) Lung cancer), 36 carcinoids and seven tumors of various types. Patients have not yet been treated for their cancer.
The researchers studied tumor genes for mutual signatures, which are patterns of mutations associated with specific interaction processes.
Damage caused by the body’s natural functions (e.g., defective DNA repair or antioxidant pressure) or exposure to cancer.
Mutual signatures act as a tumor archive of functions that lead to the accumulation of mutations, providing clues to the development of cancer.
There is currently a list of known mutual signatures, although some do not have known causes.
In this study, the researchers found that most of the genes in non-smoking tumors have mutual signatures associated with damage caused by endogenous processes, i.e. natural processes occurring within the body.
The study analysis revealed 3 subtypes of lung cancer in non-smokers
Surprisingly, since this study was never limited to smokers, researchers have not previously found any mutual signatures associated with direct exposure to smoking.
They found no such signatures among the exposed 62 patients Second hand tobacco smoke.
However, because the sample size was small, Dr. Landy warns that “non-smokers need a larger sample with detailed exposure information to truly study the impact of passive smoking on the development of lung cancer.”
The Genetic analysis They revealed three new types of lung cancer in non-smokers, which the researchers gave musical names based on the “noise” (i.e. the number of genetic mutations) in the tumors.
The The main subtype is ‘piano’ It has very few mutations; This appeared to be related to the activity of precursor cells involved in the formation of new cells.
This tumor subtype grows very slowly over many years and is difficult to treat because it can have a variety of drive mutations.
The ‘Semi-strong’ subtype It consisted of specific chromosomal changes and mutations in the EGFR growth factor receptor gene, which usually transmitted into lung cancer and showed rapid tumor growth.
Finally, the ‘Strong’ subtype There was a genetic mutation, a genetic mutation commonly found in lung cancers from smokers. This tumor subtype also grows rapidly.