Around 1.4 million new cases of cancer are linked to viruses, according to the American Society for Microbiology. The alarming analysis also found that one in five cancer-related deaths can be traced back to a virus or bacteria.
While it is often advised that a healthy diet and lifestyle can help prevent cancer, there has been less advice on which viruses and bugs are linked to the deadly disease. It is thought that bowel cancer, cervical cancer, liver cancer and Hodgkin lymphoma are among the cancers that a viral infection could trigger.
Viruses can weaken the body’s defences enough for cancerous cells to sneak past health barriers and start multiplying.
A recent study found a particular infection could be behind the surge in the number of young people diagnosed with bowel cancer. Bowel cancer kills almost 17,000 a year in the UK and its rate is skyrocketing among younger Britons.
Those aged between 25 and 49 have seen rates rise by 22 percent in the early 1990s.
Dr Charles Swanton, chief clinician at Cancer Research UK, has suggested that the dramatic rise could be tied to a childhood bug. In a recent interview, he said that a particular strain of E. coli, PKS-positive E. coli, could be linked to the bowel cancer rates.
The particular E. coli strain is thought to release a toxin that damages the cells lining the bowel, increasing the likelihood they become cancerous over time.
There are theories that the strain is tied to Western diets high in processed meats and sugar. A 2022 study from Harvard Medical School found that the risk of developing bowel cancer increased after people had become infected with this type of E. coli.
After tracking almost 135,000 volunteers over four years, those on high-fat, high-sugar diets were more likely to develop bowel cancer. Those that were diagnosed with bowel were also over three times more likely to have PKS-positive E. coli in their tumours.
However, it is not just bowel cancer that a virus can help trigger.
Almost every case of cervical cancer – which kills around 850 people a year in the UK – is traced back to several types of human papillomavirus (HPV), an infection spread by close contact, often during sex.
Fortunately, an HPV vaccine for girls aged 12 to 13 in the UK, covers most strains associated with cervical cancer. The vaccine has also been offered to boys since 2019. The rates of HPV have fallen by around 90 percent in the UK since the jab was introduced and there are hopes that cervical cancer could even be eradicated in the UK by the end of the decade.
Hepatitis C – which affects more than 60,000 people in England – is another virus that causes long-term inflammation in the liver. A Hep C infection can eventually in some cases lead to cancer cells.
However, just like HPV, treatment with antiviral tablets is readily available and can clear a Hep C infection before cancer becomes a risk.
The Epstein-Barr Virus, which causes glandular fever, is thought to be linked to around 40 percent of Hodgkin lymphoma cases. The aggressive cancer affects more than 2,000 people a year in the UK.
Lawrence Young, a virologist and professor of molecular oncology at the University of Warwick, explained that cancer is often linked to persistent viruses and not an everyday cold.
He told Mail Plus: “Normally it’s viruses – like HPV – that persist for long periods in our bodies which are associated with cancer. We are talking about long-term viral infections where the virus sits inside your cells for years at a time. You won’t get cancer from having a cold.”
Professor Young has warned against panic, saying that becoming infected with a virus or bacteria does not mean you’re likely to get cancer.
The University of Warwick professor said: “For example, around 95 percent of us have Epstein-Barr virus in our bodies yet the vast majority of us will not develop cancer as a result. The virus is one link in a whole chain of events that cause cancer but if you break that chain – as we do with the vaccine for HPV – then you can stop the cancer forming.”
Stephen Griffin, professor of cancer virology at Leeds University, added: “Long-term viruses, like HPV or hepatitis C, increase the hallmarks of cancer – such as DNA not being repaired properly, cells multiplying when they shouldn’t or inflammation.”