(RxWiki News) Viruses don’t just cause the common cold. No, these germs can be involved in far more serious diseases, including cancer. At one point, scientists believed nearly half of all tumors were caused by viral infections. A new study says that figure is way too high.
Researchers have eliminated a number of cancers once believed to be associated with viruses after examining nearly 4,000 tumor samples.
These findings, the researchers suggest, will help to narrow the focus of research so that potential therapies can be developed.
"Talk to your doctor about your vaccination status."
Xiaoping Su, PhD, associate professor of bioinformatics at The University of Texas MD Anderson Cancer Center, and colleagues conducted this study to learn more about the role viruses play in the development and progression of cancer in humans.
For years, scientists believed that viruses were involved in 10 to 20 percent of cancers. That number jumped to 40 percent following a Swedish study that concluded viruses were part of brain and prostate cancer tumors.
It has long been known that the human papillomavirus (HPV) is linked to a number of cancers, including cervical and other gynecological cancers, anal cancers and head and neck cancers.
Infection with the hepatitis B virus over time can lead to liver cancer. And the Epstein-Barr virus has been seen in gastric (stomach) and liver tumors.
To learn the nature of viral involvement in other cancers, the researchers examined 3,775 cancer tumors acquired from The Cancer Genome Atlas. A mathematical model was then used to determine if viruses were present in these samples.
What the researchers discovered is that viruses were not associated with acute myeloid leukemia (blood cancer), cutaneous melanoma (most serious form of skin cancer) and brain tumors called gliomas.
Also, viruses were not seen in adenocarcinomas (types of cancer that attack the epithelium, or the surface of the skin, glands and other tissue) of the breast, colon and rectum, lung, prostate, ovaries, kidneys and thyroid.
The researchers also discovered how viruses interact with the genetic makeup of cancer cells.
According to Dr. Su, these findings can help further research on personalized therapy.
Future therapies could target the sites where the genes of the cells and the viruses interact to fuel the development and progression of cancer.
This study was published in the August issue of the Journal of Virology.
The research was supported by TCGA grant, National Center for Research Resources grant and The University of Texas MD Anderson Cancer Center support grant. No conflicts of interest were reported.