Cancer find raises hope for vaccine

By MARTIN JOHNSTON health reporter

A New Zealand-led study has uncovered a link between breast cancer and a common virus, raising hopes of a vaccine for the leading cause of cancer deaths among New Zealand women.

Scientists in Europe and the United States are already working on experimental vaccines to protect against the virus, called cytomegalovirus (CMV).

CMV is spread by bodily fluids, including breast milk, saliva and semen. Related to the herpes and chickenpox viruses, it is usually without symptoms in young children, but in adults can cause glandular fever, an illness characterised by fever, tiredness and swollen lymph glands.

A study by Otago and Melbourne Universities is the first to link the virus to breast cancer.

Each year more than 2000 New Zealand women are diagnosed with breast cancer and around 650 die from it.

The Otago and Melbourne study suggests women infected by the virus in adulthood are at higher risk of developing breast cancer than those exposed as children.

Other viruses have been tentatively linked to breast cancer and viral causes of liver and cervical cancers are well established.

International trials are under way of vaccines targeting the viruses that cause most cervical cancer and a vaccine is in use against one of the liver cancer viruses.

"The most exciting possibility would be, if that were the case, maybe further down the track somebody could develop a vaccine," said the lead researcher, Dr Ann Richardson, of Otago University's Christchurch School of Medicine and Health Sciences.

"It could be given to young children and it would protect people against being exposed late in life because they already would have developed antibodies when they were young."

Cancer Society medical director Dr Peter Dady, a cancer physician, said the findings were exciting because they showed the significance of delayed exposure.

While not proving that CMV caused breast cancer, the study strengthened the theory. If proven, this could lead to the development of a vaccine to knock out one pathway to breast cancer, he said.

The study tested blood samples from 377 women aged under 40.

Antibodies to CMV - indicating previous exposure - were 22 per cent higher on average in women with breast cancer than in those without it.

Dr Richardson said this suggested the women with breast cancer were infected with the virus more recently than the others.

Breast cancer rates are higher in the West than in developing countries. But the West has lower rates of infection with CMV, at 60 to 70 per cent of adults.

The Cancer Society, which helped finance the study, and the Breast Cancer Foundation welcomed the findings. "It's a very interesting association, but I think it would need further study to ratify it," said the foundation's medical committee chairwoman, Dr Belinda Scott, a breast surgeon.


CANCER LINK

New Zealand-led research links breast cancer to a virus called cytomegalovirus.

Women with breast cancer have higher levels of antibodies to the virus.

This suggests viral infection as an adult, but not as a child, may be a risk factor for breast cancer.

Development work under way on a vaccine against the virus.