Transmissible venereal tumor (TVT) is an 11,000 year old cancer, says Dr. Elizabeth Murchison, lead researcher with Wellcome Trust Sanger Institute. They decoded the DNA of the tumor taken from an affected dog and not only discovered the cancer’s historical age, but also its origin, a husky-like primitive canine. The cancer literally “jumped into other dogs”, transforming (or mutating) a million times over the centuries. TVT is a sexually transmitted, highly contagious cancer. The question is raised, are there contagions that cause cancer in humans?
“The genome of the transmissible dog cancer will help us to understand the processes that allow cancers to become transmissible,” said Prof Sir Mike Stratton, Director of the Sanger Institute.
Helen Briggs with the London BBC says, “this ancient cancer existed in an isolated group of dogs until only 500 years ago.” The most supported explanation is that our early sea-faring explorers, who were often accompanied by hunting dogs, came into contact with the infected canines. When they were discovered, the travelers either boarded these dogs on their ship, or the infected dogs mated with the travelers’ dogs prior to their departure.
So how does this translate for a human’s health?
The American Cancer Society makes it very clear that a healthy person cannot catch cancer from someone who has cancer. Researcher at the ACS say there is no evidence that proves cancer can spread by close contact, sharing utensils, or walking in the same vicinity as a sick person. However, cancer causing organisms can exist and increase your chances of acquiring the disease.
The viruses that have proven to be associated with various cancers are the human papilloma virus, Epstein-Barr virus, hepatitis B and C, herpes simplex virus, and human T-lymphotrpic virus-1.
The viruses named are only some of the organismal agents that increase your risk of cancer. There is also a bacterium, Helicobacter pylori, that has been linked to stomach cancer. Not only has the H. pylori bacterium been found associated with this disease, but in 80 percent of stomach ulcer cases, H. pylori is the cause (2005 Nobel Prize for Physiology or Medicine winners, Dr. Barry J. Marshall and Dr. Robin Warren). It is not exactly known how the H. plyoi bacterium is spread, but some actually view this as proof that some cancer can be contagious in humans as well.
Finally, the last cancer causing (or influencing) organism on the list by the American Cancer Society is the parasite. Because there is not much information on the ACS’s website for this correlation, Dr. Simon Yu explains her take on parasites, inflammation and degenerative disease. Many doctors have known for a very long time there is a relationship between infection and cancer. Yu introduces Jean Marie Houghton, MD, Ph. D from the University of Massachusettes Medical School who has found that infectious microbes are hidden by inflammation, and in this toxic environment cancer cells can grow. Low-grade fever is one of the signs of infection, but this can be overlooked for a number of years leading to disease and chronic illness like cancer.
There is a bridge between Dr. Simon Yu’s research and the research done at the American Cancer Society. The ACS clearly states that the effect which germs play on cancer in people is an indirect role. Germs will cause an inflammatory response and will weaken a person’s immune system. Cancer is usually caused by mutations in our DNA from sun exposure, or cigarette smoke, car oil, and anything named to be a carcinogen (or have YET to be named).
Does canine cancer directly affect humans in anyway? Many hope not, but the finding of a cancer with a DNA structure so unique will have researchers scrambling to find funding for future research. It also brings to light the knowledge and research already available for decades about infection and cancer. Is cancer contagious? For some species and in some unique circumstances the answer is, yes. And in humans, the causes of some cancers are currently known to be contagious.
By L.P. Alexander