Australian scientists have discovered what they believe to be the ‘cell of origin’ that gives rise to a deadly form of lung cancer that affects both smokers and non-smokers alike, according to new research.
Researchers from the Walter and Eliza Hall Institute in Melbourne, led by PhD student Clare Weeden and Dr Marie-Liesse Asselin-Labat, have revealed how basal stem cells in the lungs can lead to the formation of lung squamous cell carcinomas. The study was published in the scientific journal PLOS Biology.
Lung squamous cell carcinoma is the second-most common subtype of lung cancer and accounts for around 30 per cent of all lung cancer cases.
“We think that these are the cells that the first genetic mutations occur in that lead to lung squamous cell carcinoma forming,” Ms Weeden told The New Daily.
Using donated lung tissue samples from the Victorian Cancer Biobank, the team investigated basal stem cells in the lung airways and found that when exposed to harmful chemicals such as cigarette smoke, they would repair damage to surrounding lung tissue.
However, these stem cells were also found to have a faulty, or “error-prone”, DNA repair process that made them more susceptible to the accumulation of genetic mutations that can ultimately lead to cancer formation.
“These cells have to first fix their own DNA, and the way they fix their own DNA so they can survive is through this really quick process that just happens to be more error-prone,” Ms Weeden said.
Ms Weeden made the discovery when she noticed that basal stem cells from a heavy smoker were growing much faster than those from a non-smoker.
“The reason why these basal stem cells from smokers were so active was because they were able to repair any DNA damage from the cigarette smoke so quickly but in this error-prone way,” she said.
Genetic analysis confirmed a correlation between basal stem cells’ genetic signatures and cancerous cells, which gives strength to the idea that they are, as dubbed by the researchers, the ‘cell of origin’.
One of the reasons why lung cancer is so deadly is that by the time the cancer is discovered, often due to the way it mimics other lung diseases, it is already in an advanced stage and often inoperable.
Professor Sanchia Aranda, CEO of Cancer Council Australia, said the research was exciting because it could lead to the development of more accurate diagnostic tools.
“Early diagnosis is the ‘holy grail’ in lung cancer,” Prof Aranda told The New Daily.
Lung cancer causes more deaths than breast, prostate and ovarian cancers combined but lung cancer research receives around five per cent of cancer research funding in Australia, which Prof Aranda says is linked to a lack of survivor advocacy.
“Survival from lung cancer sits at less than 20 per cent, so survivors tend to feel guilty or stigmatised by their diseases, particularly if they were smokers,” she said.
“So the advocacy’s not been there and that hasn’t encouraged a generation of researchers to move into lung cancer [research].”
A third of cancers in Australia, which is around 37,000 cases per year, are preventable and about 15,000 of these are related to tobacco smoke.
However, about 15 per cent of lung cancers occur in people who have never smoked cigarettes before but are still a victim of that stigma.
“I think everyone regardless of their lifestyle choices deserves research and the best possible treatment for their disease, especially one that is so prevalent in Australia,” Ms Weeden said.
Both Ms Weeden and Prof Aranda think attitudes toward lung cancer are changing, but stressed the importance of maintaining anti-smoking health campaigns.
“The most important thing that you can do for prevention is to not smoke,” Aranda said.