A vaccine that destroys advanced prostate cancers while leaving healthy tissue untouched has been developed by scientists.
In laboratory tests, the gene therapy jab successfully wiped out 80 per cent of cancers without causing serious side effects.
The British researchers behind its creation said it was a 'completely new approach' and predicted that it could start trials on people within a few years.
Although the jab has been tested on prostate tumours, they believe it could work on a range of other deadly cancers including breast, lung and pancreatic cancer.
Unlike a conventional vaccine which is given to prevent infection with a virus or bacteria, the new treatment is used after someone has contracted cancer.
Prof Alan Melcher, from the University of Leeds, who co-led the research, said clinical trials could be underway within 'a few years' and that the same technique could work for a host of cancers.
‘So far it looks safe and if it continues to look safe there’s nothing we wouldn’t rule out,’ he said.
Vaccines work by stimulating the body’s immune system to recognise antigens - distinctive proteins that are found on surfaces of cells.
Most vaccines are designed to teach the body to seek out and destroy viruses or bacteria. However, scientists are also vaccines that provoke an immune response to cancer cells.
The new cancer jab is a form of gene therapy.
Researchers first created a library of thousands of randomly-selected snippets of genetic code taken from a healthy prostate and then inserted them into a virus.
The modified virus was then cultured in a laboratory and then injected into the bloodstream of a mouse with prostate cancer.
When the mouse’s immune system was exposed to the modified virus, it produced an array of antibodies – each one geared up to recognise a different antigen on the surface of a prostate cancer cell, the researchers report in Nature Medicine.
Professor Richard Vile, of the Mayo Clinic in Rochester, Minnesota who took part in the study said: 'Nobody really knows how many antigens the immune system can really see on tumour cells.
‘By expressing all of these proteins in highly immunogenic viruses, we increased their visibility to the immune system.
'The immune system now thinks it is being invaded by the viruses, which are expressing cancer-related antigens that should be eliminated.’
Progress has already been made towards developing a similar vaccine treatment for melanoma, the most dangerous form of skin cancer.
Past attempts at gene therapy cancer vaccines often used just one gene from a tumour cell to stimulate the immune system.
But finding the right gene has proved difficult. And using two or more genes has raised fears that the immune response would be too strong for the patient to handle.
The researchers used two versions of the vaccine – one based on human prostate tissue, the other using mouse tissue. Both worked, although the human version was more effective.
Injecting the vaccine into the blood, rather than the tumour itself, appeared to prevent the immune system going into 'overdrive' and attacking healthy tissue.
Prof Peter Johnson, of the charity Cancer Research UK, which funded the Leeds team, said: 'Although the vaccine didn’t trigger the immune system to overreact and cause serious side effects in mice, it will need to be further developed and tested in humans before we can tell whether this technique could one day be used to treat cancer patients.'
Each year around 35,000 men in the UK are diagnosed with prostate cancer and 10,000 die from the disease.
Dr Kate Holmes, research manager at The Prostate Cancer Charity, said: 'This study provides new hope for the potential of these new anti-cancer therapies.
‘Although we are hopeful that the results of this study could help to form the basis of a new cancer vaccine in future, it is important to remember that the researchers have only investigated the potential of their vaccine in mice.
‘Further research looking at its effect in men is needed before we can be sure of the usefulness of this vaccine. We look forward to the outcome.'
source: dailymail.co.uk
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