How vaccines can prevent cancer, reports Cancer Research UK

Vaccines against specific viruses could prevent one in 10 cases of cancer in Britain, according to a new report by Cancer Research UK. This estimates that a handful of infections can trigger around one quarter of cancer cases in the developing world and suggests that vaccines could stop them. The authors stress that people cannot "catch" cancer. But some viruses can initiate the disease in a small proportion of those infected. Almost all kinds of cancers develop through a series of genetic accidents. When the accidents accumulate a cell can become cancerous. For some sorts of cancer one of these genetic accidents is linked to infection, the report notes.

Cancers linked to infection with particular viruses include cancers of the cervix, liver and nasal passages (nasopharyngeal carcinoma), as well as certain types of lymphomas including some Hodgkin's lymphomas and rare forms of leukemia. Many cases of stomach cancer are also linked to a common bacterial infection. Although only a small proportion of virus-infected people develop these cancers, the global number of virus - associated cancer accounts for more than 1.8 million new cases of cancer each year - which is around 18% of all new cancer cases worldwide.

Alan Rickinson, from the Cancer Research UK Institute at the University of Birmingham and lead author of the report, said: "studying the association between infectious agents and human cancers is extremely important because, in such cases, infection represents one defined link in the chain of events leading to cancer development. Knowing this helps us to trace other links in the chain and to understand how the whole chain fits together. More importantly, if we can break the chain by preventing the infection through vaccination, then we can prevent the cancer developing."