According to a paper published last week in The Lancet: Oncology 16 percent of cancers are caused by infection with a virus - meaning there are more than two million new cancer diagnoses attributable to infection each year. This number varies from country to country - in Sub-Saharan Africa almost one third of cancers have a viral origin - but no matter how you look at things this represents a fundamental change in the public conception of cancer. It's still a condition where cells are growing out of control, but now we know that many of them have a trigger.
Although it might not sound like it at first, this is actually good news. Two of the most common triggers - hepatitis B and HPV - are preventable by vaccine. A third, Helicobacter pylori, can be treated with antibiotics. This means that there are real, tangible ways for doctors to reduce the impact of cancer on human health.