Scientists Discover Cells That Start Lung Cancer in Smokers
British scientists have identified cells that could be the starting point for the development of a dangerous type of lung cancer linked to smoking. The changes start in the trachea and then spread throughout the lungs, crowding out healthy tissue. The discovery could help diagnose and prevent squamous cell lung cancer more quickly in the future.
A team of scientists from University College London (UCL) , the Wellcome Sanger Institute and the University of Cambridge have conducted a medical study that could change the way we approach early detection of lung cancer in humans . The study focused on lung squamous cell carcinoma (LUSC) – the second most common subtype of lung cancer , and is particularly dangerous for people who smoke and are exposed to carcinogens .
Studies of cancer cells have shown that cancerous changes in the respiratory system begin in a specific group of cells in the trachea, part of the respiratory tract .
These are the so-called basal cells of the respiratory system , which produce the Krt5 protein – an important structural protein for cellular structure . It is from them that the process of cancer begins. Over time, cancer cells displace healthy lung cells and take control of an increasingly large area of lung tissue .
As Prof Sam Janes of UCL said:
- The descendants of just a few cancer cells derived from the basal cells of the trachea attack and defeat normal cells , in some cases colonizing entire lobes of the lung .
During medical experiments on laboratory mice, scientists marked cells with the Krt5 protein and observed their development over time. One group of animals was exposed to carcinogens that mimicked the effects of smoking , environmental factors that increase the risk of lung cancer . In this group, the cells began to divide, grow and spread throughout the lung tissue . In the second, control research group , where there were no toxic chemicals , the cells remained in place.
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Conclusion? It is exposure to carcinogens, such as tobacco smoke , that triggers cancer processes and disrupts the natural cellular balance in the respiratory tract .
Normally, in the human respiratory system there is cellular homeostasis , i.e. a balance between different types of cells – there are basal cells (acting as stem cells of the respiratory tract) , as well as luminal cells, which protect the interior of the lungs and are responsible for the proper functioning of the respiratory epithelium .
As Dr Sandra Gómez-López from UCL explained:
- Under normal conditions, basal cells in the respiratory system give rise to new basal cells or luminal cells of the respiratory epithelium .
But tobacco smoke , containing carcinogens and toxins , changes everything. The biological balance in the respiratory tract disappears. Single damaged cells with cancerous properties begin to dominate and disrupt the functioning of the entire respiratory system .
What’s more, analysis of RNA (the genetic material of cells) from the trachea of mice and humans showed that as the damaged Krt5 cells grow, more transitional cells appear with another gene, Krt13, associated with further development of cancerous changes . This could be the next step in cancerous transformation and tumor formation .
The discovery of the so-called “lung cancer progenitor cell” opens up new possibilities. Scientists now want to design preventive strategies that will help stop lung cancer before it fully develops—or at least catch the disease in its early stages , when lung cancer can still be treated more effectively .
As Prof. Sam Janes summarizes:
- Understanding where the process of lung cancer begins and how it develops can help prevent respiratory cancer .
This is a step towards a more effective fight against cancer , which claims a huge toll in deaths around the world every year.
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