Bowel cancer treatment breakthrough as scientists solve decades-long immune system mystery
A NEW treatment for bowel cancer could be on the cards after scientists solved a decades-long riddle about why the body does nothing to fight the disease.
Researchers at the University of Glasgow and Cancer Research UK's Beatson Institute discovered how bowel cancer blinds the immune system so it cannot see the cancer and renders it unable to destroy it.
They found cancerous cells hide in plain sight by "disguising" themselves as stem cells to avoid being detected.
Dr Seth Coffelt, who led the research, said: "Normally, immune cells keep things as they should be, patrolling the bowel like security guards, tackling any harmful bacteria and keeping the gut healthy.
"However, when cells in the bowel become cancerous, they fire these 'security guards' and all the methods these immune cells use to talk to each other to co-ordinate an immune response no longer get produced.
"Cancer doesn't want immune cells recognising them as a threat, so they manipulate the immune cells so they can't see the threat and simply pass on by leaving the cancer to do its damage."
The team said the discovery, published in Cancer Immunology Research, a journal of the American Association for Cancer Research, opens the door to potentially reversing or preventing this process.
It would allow the immune system to see the bowel cancer cells and stop them from growing and multiplying.
Bowel cancer is the second most common cause of cancer death in the UK, with about 16,800 deaths every year - or 46 every day.
In Scotland, around 4,000 people are diagnosed with the disease every year.
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As part of the work, the Glasgow-based researchers focused on a particular type of immune cell called gamma delta T cells.
Bowel cancer begins in the epithelial cells which line the bowel and these T cells patrol this area attacking any threats, such as damaged cells or small tumours, before they cause harm.
Scientists already knew that when bowel cancer is present, immune cells that can kill cancer do not often act against it, but they did not know why.
Using tissue samples from bowel cancer tumours donated by patients in Scotland, and other countries, scientists were able to identify the specific mechanism the cancer cells use to rewire the gamma delta T cells on a molecular level.
The team which made the discovery is now hopeful further research could offer treatments which could reverse that process.
Discovering how the cancer cells trick the immune system offers potential for new treatments which could reactivate these immune cells, researchers said.
Dr Coffelt added: "Our discovery means that if a way can be found to artificially engage the 'blinded' T cells with a drug so that the T cells can see the cancer again, we could find a new effective way to treat bowel cancer."
The research also won funding from the Medical Research Council and the Wellcome Trust.
What are the symptoms of bowel cancer?
BEING aware of the signs and symptoms of bowel cancer, spotting any changes to your normal toilet habits and going to your doctor are vital.
If you notice any of the signs, don't be embarrassed - chances are your GP has heard it all before.
The five red-flag symptoms of bowel cancer include:
- Bleeding from your bottom and/or blood in your poo
- A persistent and unexplained change in bowel habits - going more frequently for example
- Unexplained weight loss
- Extreme tiredness for no obvious reason
- A pain or lump in your tummy
Tumours in the bowel typically bleed, which can cause a shortage of red blood cells, known as anaemia. It can cause tiredness and sometimes breathlessness.
In some cases bowel cancer can block the bowel, this is known as a bowel obstruction.
Less common symptoms include:
- Abdominal discomfort
- Gas and bloating
- Nausea and/or vomiting
- Fever
- Air bubbles in your urine
- Problems breathing
- Headache and neurological problems
- Bone pain
The two best ways to protect yourself are to know the signs and symptoms and to take up the invitation for NHS screening when you become eligible.
Depending on where you live, this starts aged 50.