Scientists have developed a vaccine that they say provides some protection against brain tumours in mice.
The vaccine works by boosting the immune system to attack abnormal cells.
The approach has not been tested on humans, but clinical trials could begin next year in Germany, say researchers.
Brain tumours are difficult to treat so more research is urgently needed to give patients better options, said a cancer charity.
A team at the National Centre for Tumour Diseases in Heidelberg developed a vaccine that targets brain tumour cells.
It is based on the natural ability of some patients with brain tumours to mount an immune response against the disease - although this is not enough to stop the tumour growing.
The mouse experiment showed that a vaccine may be able to boost this natural approach, the researchers said.
"We can induce an immune response that is similar to what we see in some brain tumour patients who have a natural immunity but it is not strong enough to take care of the tumour," said Prof Michael Platten.
The team is applying for approval to start a human clinical trial in Germany next year.
"It's still too early to know if the vaccine will be efficacious in humans," he added.
"Using the immune system to attack cancer is an exciting approach to tackling the disease and this research is another step forward in finding new treatments," said Dr Emma Smith, senior science information officer.
"But this is a very early-stage study and was carried out in mice, so much more research is needed before we know if the vaccine is safe or effectively boosts an immune response against brain tumours in people.
"Brain tumours are a diverse group of cancers and are difficult to treat, so we urgently need more research to give people better options."
Other researchers around the world are looking into similar vaccines to stimulate the immune system to fight off cancer.
A trial started in the UK last year into a similar vaccine to fight brain tumours.
The approach, known as immunotherapy, is also being tested in the US.