Dr Alexander Knuth, of Krankenhaus Nordwest, Frankfurt, stressed that it was too early to claim a cure but said: "I think this is a landmark in the immunology of cancer." Other researchers at the annual meeting of the American Association for the Advancement of Science in Baltimore believe other cancer vaccines may be possible, including one for cervical cancer.
Malignant melanoma, which is on the increase in western Europe, is curable if detected early enough and the tumours are surgically removed. But otherwise it is usually fatal, Dr Knuth said. He is confident that this new approach will advance treatment of the disease.
In one of three patients treated this way, the tumours vanished while in the others there was significant regression - shrinkage of the cancer.
The vaccine was developed from the tumour cells of two patients who had melanoma in the late 1970s. At that time, Dr Knuth took their cancer cells, irradiated them to kill them, and then re-injected them into the patients' skin. The injections triggered "killer cells" of the immune system to recognise and attack the cancer cells as if they were invading microbes.
Both patients - a 38-year-old American man and a 51-year-old Frankfurt woman - made complete recoveries. For some reason, these two had a particularly strong immune response to their tumours, stimulated by reinjection of their own cells.
In his most recent work, leading to the three patients showing complete or partial remission, Dr Knuth and his colleagues analysed the cells of the earlier patients to find the active fragments which triggered the immune response. They then synthesised these fragments for use as the new anti-cancer vaccine, rather than using whole cells.
At Johns Hopkins University in Baltimore, researchers have developed a genetically engineered vaccine which arms the immune system to destroy cervical cancer cells in laboratory animals, with no side-effects. Human clinical trials are expected to begin in about a year.
This vaccine takes advantage of the fact that 90 per cent of human cervical cancer is due to a virus, human papilloma virus. The vaccine delivers a molecular tag which activates immune cells, known as CD4 cells, to recognise it as foreign and then call out the killer cells to destroy anything - including the tumour cells - carrying that tag.
According to Dr Drew Pardoll, of the Johns Hopkins oncology department, "the CD4 cell is the key to an immune response. In cancer, the immune system remains dormant because the CD4 cells never get the message that it is being attacked and therefore never activate the killer cells".
The vaccine makes sure that the CD4 cells are properly activated. But finding the specific fragment that stimulates an immune response can be time-consuming and many cancer cells do not have tags that make them different to normal cells.
t Scientists at the Imperial Cancer Research Fund have developed a new range of sun blocks that prevent tanning. Doctors say sun worshippers are continuing to ignore warnings about the danger of tanning.
More than 40,000 sufferers are likely to be diagnosed with skin cancer this year. Researchers say the new Sun Safe block uses titanium chemicals that protect by reflecting sunlight.Reuse content