Could a Cow Virus Cause Colon Cancer?

The remote possibility that I might develop mad cow disease as a result has never stopped me from diving into a nice juicy hamburger (preferably with a generous helping of ketchup and relish). But that was before I heard Harald zur Hausen hypothesize that a cow virus might be responsible for most cases of colon cancer. And why should anyone pay attention to what Harald Zur Hausen thinks? Well, he won a Nobel Prize in 2008 for proving that most cases of cervical cancer are caused by a few strains of Human Papilloma Virus (HPV). Nor is HPV the only viral cause of cancer. Chronic infection with certain hepatitis viruses, for example, is a major cause of liver cancer. Zur Hausen’s intriguing line of evidence consists mostly of provocative questions that take on the received wisdom—questions that he is more than willing to follow with further investigation of the sort that will eventually prove his hypothesis right or wrong. For example, the received wisdom is that the connection between red meat and an increased risk of colon cancer has something to do with the number of heterocyclic amines that form during the cooking of red meat. And yet, zur Hausen reported, “fried, grilled or smoked fish or chicken actually have the same or higher concentration of heterocyclic amines as red meat.” In other words, why would heterocyclic amines be a problem for one kind of cooked meat, but not another? Then zur Hausen relayed the curious fact that the country of Mongolia has very low colon cancer rates, but it also has highest meat consumption per capita of any country in the world. Perhaps the fact that Mongols eat mostly yak, mutton goat, canned meat and horsemeat has something to do with the apparent mystery. Colon cancer incidence is relatively low in India (where vegetarianism is quite prominent), some Arabic countries (where goat is more common) and Bolivia as well, zur Hausen said. The Bolivian situation is a bit complicated by the fact that so many of the beef cattle there appear to be mixes from different species...more