New 'shotgun' vaccine seeks and destroys cancer cells

Scientists have developed a vaccine to combat prostate cancer which could be ready to use in just a few years.

The vaccine works by priming the immune system to seek out and destroy prostate tumours while ignoring healthy tissue.

The same approach could also be used against other cancers, including the disease that affects the lung, brain and pancreas, experts believe.

Campaigners welcomed the latest research, published in the journal Nature Medicine, but said further work was needed before trials in patients could begin.

In Scotland there are around 2,700 cases of prostate cancer diagnosed each year and almost 800 deaths.

Professor Alan Melcher, from the University of Leeds, and US colleagues at the Mayo Clinic in Minnesota, have developed what is described as a "shotgun" vaccine to tackle advanced prostate cancer.

It works by blasting the immune system with thousands of pieces of prostate protein DNA, with some of these recognised by the body as targets.

Once the immune system has been stimulated with this information, it looks for the same proteins in the body and as these can be found in tumour cells, they are attacked and destroyed.

The vaccine has been used to cure laboratory mice suffering from prostate cancer. The animals suffered no side effects.

This method, deploying a whole library of DNA fragments to fight the tumour, has overcome a key obstacle in the development of cancer vaccines - getting the immune system to recognise the cancer as the enemy.

The antigens - the substances to induce an immune response - were delivered into the body in a virus.

Prof Melcher said: "This meant the immune system was made to recognise them as a threat. But, crucially, the research showed this did not lead to healthy tissue being targeted.

"When we vaccinate with this virus, these antigens get made which the immune system recognises and attacks.

"Because the cancer also makes these antigens, when the immune system is stimulated in this way, it attacks the tumour."

Researchers in the US believe clinical trials of the vaccine could start within two years.

Prof Melcher said: "I think that's a little optimistic and we're talking about a few years.

"It is very early days in terms of applying this to patients. What we can say is that viruses similar to the one that we used here have been used in (vaccine] trials and are looking quite promising, so the platform is there and appears to be safe and deliverable."

Professor Peter Johnson, from Cancer Research UK, 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."