German scientists take major step towards developing vaccine against cancer

German scientists have taken a major step towards developing a vaccine against cancer.

While vaccines were mostly known for their preventative role, the latest study, published in the journal Nature, outlined a vaccine strategy against existing tumours that harnessed the immune mechanisms that the body uses to combat viral infection.

The technique which is being hailed as "promising", is in early clinical trials had only been tested in mice and three patients with advanced melanoma.

According to scientists, it raised the possibility of a universal vaccine for cancer immunotherapy.

The findings raised the question: "why have our bodies not evolved to spot the spread of cancer and launch a defence against it?"

One important reason was that cancer cells were similar to normal cells and the immune system avoided attacking them.

Another reason was that as cancer spread, it managed to evade sending out strong inflammatory signals that would stimulate an immune response.

In a 'Trojan horse' strategy, scientists had created under laboratory conditions, nanoparticles containing cancer RNA were injected into the subjects to help the body identify invasion by a viral pathogen.

They targeted immune system cells called dendritic cells in mice experiments, using an intravenously administered vaccine made up of RNA nanoparticles.

They found that by making the net electrical charge of the nanoparticles slightly negative they could efficiently target these dendritic cells.

By just changing the RNA inside the nanoparticles, the immune system could be mobilised against any kind of cancer. ''Such vaccines are fast and inexpensive to produce, and virtually any tumour antigen can be encoded by RNA,'' the team, led by researchers at Johannes Gutenberg University of Mainz in Germany, Nature reported.

''Thus, the nanoparticulate RNA immunotherapy approach introduced here may be regarded as a universally applicable novel vaccine class for cancer immunotherapy.''

Immunotherapy, involving the use of the patient's own immune system to attack cancer, was not in itself new; researchers had been using it against different cancer types with great results.

But until now, researchers had mostly taken the route of genetically engineering special, cancer-targeting immune cells in the lab, and then injecting them back into a patient which was a  time-consuming and expensive process.

The difference with this technique was that the vaccine is made in the lab, and it introduced the cancer DNA into the immune cells within the body, which was a lot less invasive. It also meant that the vaccine could be tweaked to hunt a range of cancer types.

(Also see: German researchers propose Trojan horse strategy to fight cancer)