At least one out of every seven cancer disease directly or indirectly caused by viruses. An international team of researchers has now investigated, what is the causative agent for what disease is responsible. Thus, the scientists hope to prevent the development of certain types of cancer in the future.
Viruses, bacteria, worms – according to estimates by the world health organization on diseases 15 per cent of all cancers to infectious pathogen causes. A total of eleven different pathogens, the international cancer research Agency IARC classifies as carcinogenic. One out of every ten cancers is thus to such pathogens. Alone of 640,000 cases of cancer, the researchers the result of a year on the human papilloma virus.
A Team of international scientists looked at which viruses with what types of cancer are associated. The genome researchers, headed by Peter Lichter from the German cancer research center (DKFZ) wanted to search for viruses that were not yet produced with the development of cancer, or completely unknown.
In the case of virus-induced cancers, prevention is possible
“The question is, what viruses are associated with cancer, and, for the medicine high relevant", Marc Zapatka from the DKFZ, the first author of the current study is explained. “Because in the case of virus-related cancers is real prevention possible: Is identified as a carcinogenic Virus, so the Chance of having a vaccination to prevent infection and to prevent the cancer is."
The investigations are part of the “Pan-Cancer Analysis of Whole Genomes”. It is an Association of over 1300 researchers who want to analyze the role of gene mutations or patterns of genetic changes in multiple tumor types. The scientists examined more than 2600 tumor genomes from 38 different kinds of cancer.
The DKFZ-Team discovered at 356 cancer patients, traces of 23 different pathogen types. The most common viruses that are already known for their driving effect in terms of cancer formation and growth were represented:
Epstein-Barr, Hepatitis B, and HPV
In 5.5 per cent of the cancer genomes, the scientists found the genetic material of the Epstein-Barr virus. These are considered to be the polluter of many kinds of cancer, especially lymphomas, cancers of the stomach and in the nose and throat.
For 62 out of the total of 330 cases of liver cancer have felt the effects of the researchers also Hepatitis B virus on.
Human papillomaviruses with HPV 16 were you in 19 out of 20 investigated cases of cervical cancer, as well as for 18 of the 57 neck/throat tumors prove.
In rare cases, discovered the Team in addition, a Retrovirus in kidney cancer. Also, cytomegalo virus , the scientists found a few of the stomach cancer cases. In spite of the careful bioinformatic analysis, they were able to track down, but no viruses that were previously unknown.
More on the topic of cancer
Cancer cells are immortal
Using their analysis, the scientists were able to identify the mechanisms that lead to virus-induced mutations. They realized that the virus genome is often incorporated into the human genome, in particular in the case of Hepatitis B and papilloma viruses.
“Often, we observed, for example, the incorporation of HPV DNA in the so-called Telomerase Promoter: This genetic switching element controls the production of the ‘immortality enzyme’ Telomerase is mutated in many types of cancer. We have now shown that viral integration can lead to activation of this gene age and the cells in order for immortality to give,“ explains Marc Zapatka.
Another mechanism that triggers in the genome of infected cells, the mutations, the DKFZ researchers, according to the cell’s own antiviral defense system. Cells would attack the DNA of dangerous viruses, which often leads to mutations of the cell’s own genome. The consequences are then, for example, cervical cancer, and neck/throat tumors after a HPV infection.
Study leader Peter Lichter explains in conclusion: “the analysis of complete cancer genomes, we have detected significantly more tumors the traces of virus as in previous studies, based only on the study of the RNA. Nevertheless, we could not confirm the often expressed suspicion that other, previously unknown viruses are associated with cancer."
The results of the investigation, he nevertheless sees as an important step in the fight against cancer. “In many cases we are seeing now, however, clearer on the way in which the pathogen cells and a vicious degenerate can."
You can see in the Video: disease of the pancreas: What are the signs you should not ignore
Deutsche Welle you can See in the Video: disease of the pancreas: What are the signs you should not ignore