The late morning in Lindau was a non-stop marathon of medical researchers – first Harald zur Hausen talked about the links between infections and cancer, then Luc Montagnier gave an insight into his research that analyzes DNA under physical as well as biological aspects – venomous tongues may have linked that talk to homeopathy. At last Francoise Barré-Sinoussi talked about the discovery of HIV and how it was faciliated by global translational research.
Concerning the history of the relationship between infections and cancer, Martin has already written a great article a few weeks ago. Professor zur Hausens lecture let the audience awestruck by the Laureate’s quick and clever demonstration of how much cancer can possibly be caused by infections. As such he mentioned of course the papilloma virus (HPV), for whichs role in cervical cancer he was awarded with half the Nobel Prize in 2008 (the other half went to Montagnier/Barré-Sinoussi). But there are several further viruses and bacterias that can be indirect causes to human cancers, as for example helicobacter pylori is linked to gastric cancer, HIV 1 and 2 increase several cancer risks due to weakening the entire immune system, tuberculosis increases the risk of developing a later lung cancer and borrelia burgdorferi is known to increase the risk of b-cell lymphomas. Zur Hausen explained how many of those viruses even introduct oncogenes into their host cells. In some cases even parasites can lead to cancers, as for example schistosoma is associated with bladder cancer – in Egypt the parasite is one of the main causes of this type cancer. Alltoghether zur Hausen estimated that 21 percent of all global cancer incidents are linked to infections – and many of them are preventable.
And zur Hausen also showed another interesting aspect that might lead to new ways to reduce cancer prevalences. In comparing risk factors for early-childhood leukemia, he pointed out that infections during our childhood in general lower the risk of developing such a cancer. However, if a high number of infections occur in the first year of life, the risk of leukemia is increased – supposedly the immune system can’t mature efficiently. This example also explained how children with a higher socioeconomic status are under this aspect disadvantage.
To prevent such infection-induced cancers he suggested to develop further vaccines so that infections can be prevented. Toghether with Prof. Ethel-Michele de Villiers he currently does research on the TT-Virus – a virus that for itself “just” harms the liver but is linked to causing brain tumours as well as promoting autoimmune diseases such as asthmatic conditions and multiple sclerosis.
The past decades have been filled with discoveries of links between cancer and infections. Not only did zur Hausens lecture encourage young medical researchers to focus on vaccines – but it also showed that there are a lot more viruses, bacterias and parasites to explore.