Cancer advance

Researchers have linked a virus to the onset of prostate cancer, producing the possibility of creating a vaccine to treat the disease.

VIRUS LINKED TO CANCER

27% of patients had virus in their tissue

A vaccine for prostate cancer came a step closer last week after US research suggested the disease could be caused by a virus. The Utah University and Columbia University medical schools found the xenotropic murine leukaemia virus (XMRV) in 27% of cancerous prostate tissue studied. The results suggest the human immune system can be harnessed to fight the disease by way of a vaccine. Experts welcomed the findings but emphasised that a causal link between the virus and prostate cancer had not been proven. Professor Margaret Stanley, of the department of pathology at Cambridge University said: “Simply finding the virus present does not necessarily mean the virus is causing the cancer. I am pro-vaccine but there needs to be considerably more research.”

PREVIOUS THEORIES

Prostate cancer was connected to diet and genes

Scientists had believed that men developed prostate cancer because of factors such as old age, a bad diet or genetic susceptibility. XMRV is a retrovirus that behaves in a similar way to HIV, both of which work by inserting copies of their DNA into the DNA of the cell they infect. It has long been known to cause leukaemia in animals, but this is the first link to humans. Other viruses have been found to cause cervical and liver cancer. The human papilloma virus (HPV) was discovered to be responsible for cervical cancer, and research this year by New South Wales University in Australia showed the same virus was also present in a significant number of breast cancers.

ATTACKING THE SOURCE

New vaccines make the body immune to the virus

Traditional cancer vaccines try to retrain the body’s immune system to attack cancer cells after they have developed. The problem is that cancer cells are not foreign bodies in the way that a virus is, so the body is being trained to attack itself. The new generation of vaccines are instead designed to target the virus. Vaccines of this kind are currently available for cervical cancer and by the end of this year they will be available for all girls aged 16-18 in Britain. HPV was a relatively easy virus to vaccinate against as its “coat” remains stable, meaning experts could target the vital element. XMRV is considerably more problematic — the virus constantly changes, so researchers will now have to find which bit of it stays stable and can be targeted by a vaccine.

CHRONIC CONDITION

Less virulent cancers are now very survivable

Treatments for cancer have considerably improved in recent years, with some cancers becoming more like chronic conditions. The five-year survival rate for breast cancer increased from 70% in the early 1990s to 78% in 2007. However, when all cancers are taken into account, the UK performs poorly against the rest of Europe. Britain’s five-year survival rate of 53% compares with a European average of 60%. Campaigners say the issue now is to provide long-term care to survivors. Ciaran Devane, chief executive of Macmillan Cancer Support, said: “It is about time the NHS acknowledged cancer is no longer necessarily a death sentence and recognised its long-term impact on people’s lives.”

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