Cancer cases traced back to viruses
Vaccines crucial to fighting off micro-invaders and preventing dangerous infection, study suggests
One in eight cases of cancer may be triggered by viruses and could be prevented by vaccination, a study suggests. Researchers analysed the DNA of more than 2,600 tumour samples, from 38 different types of cancer. They found traces of viruses in 13 per cent of the samples, and also discovered ways by which they could have triggered carcinogenic mutations. Finding new links between infection and cancer types has the potential to provide vaccines, they say.
ONE in eight cases of cancer may be triggered by viruses and could be prevented by vaccination, a study suggests.
Researchers from the University of East Anglia and global partners analysed the DNA of more than 2,600 tumour samples, from 38 different types of cancer. They found traces of viruses in 13 per cent of the samples, and also discovered ways by which they could have triggered carcinogenic mutations.
It was known that some types of virus cause cancer, such as HPV sparking cervical cancer, and the presence of Helicobacter pylori in the digestive tract leading to stomach ulcers and possibly stomach cancer.
But until now it was unknown just how many diseases could have been sparked by an infection.
Viruses were found in cancers of the liver, pancreas, stomach, head/ neck, oesophagus, cervix, lymphoid, central nervous system, breast, colon, kidney, prostate, skin, lung, uterus, ovary, thyroid, bladder, bone, bile duct and bone marrow. Experts said it showed that “real prevention” may be possible for a large number of cancers.
Dr Daniel Brewer, from UEA’S Norwich Medical School, told The Daily Telegraph: “We do not know whether the cancer has just created an environment that the viruses find attractive or whether the viruses are causing the cancer. There certainly seems to be a functional effect of viruses in the cancer in certain combinations.
“Finding new links between infection and cancer types has the potential to provide vaccines, such as the HPV vaccine, which could reduce the global impact of cancer.”
The team discovered traces of 23 different virus types in tumours from 356 cancer patients.
The team found human papillomaviruses, most commonly HPV16, in 19 of 20 cervical cancers cases and in 18 of 57 head and neck tumours.
The genome of Epstein-barr viruses (EBV), which are known to cause a number of different types of cancer (particularly lymphoma, stomach cancer and nasopharyngeal cancer), was also discovered in 5.5 per cent of the cancer genomes investigated.
And hepatitis B virus (HBV) DNA was found in 62 of the 330 cases of liver cancer. Other pathogens were occasionally found in tumours of the tissue type that they normally infect, such as cyt omega lo viruses in gastric cancer. They also found that in some cases viruses had merged with the patient’s genetic code, stopping cells from repairing DNA damage, and leading to mutations.
Dr Brewer added: “This suggests a role of impaired antiviral defence as driving force in cervical, bladder and head-and-neck carcinoma.”
In the UK, the HPV vaccine has been routinely offered to girls aged 12-13 since 2008 and boys of the same age since last September. But the new study suggests that wider vaccine programmes could have a large effect on cutting the prevalence of cancer.
Around 363,000 people are diagnosed with cancer each year, and if the new figure held up over the population, vaccinating could save nearly 50,000 people from developing the disease.
Dr Marc Zapatka, an author on the study from the German Cancer Research Centre (DKFZ), said: “The issue of which viruses are linked to cancer is highly relevant in medicine, because in virus-related cancers, real prevention is possible. If a carcinogenic virus is identified, there is a chance of avoiding infection with a vaccine to prevent cancer developing.”
The research is part of the Pan-cancer Analysis of Whole Genomes, a consortium of more than 1,300 researchers.