The question what causes cancer has been one of the most frustrating questions for scientists involved in cancer research. Despite huge amounts of funding and resource being spent on the subject, there is still an element of doubt behind what causes cancer. At the most we know what the risk factors are because most of the causes carry an element of doubt along with them.
An important risk factor behind the development of lung cancer in humans is cigarette smoking. But cigarette smoking does not cause cancer on its own because there is strong evidence of many heavy smokers who do not develop cancer. Genetic predisposition and a change in genetic messages caused by carcinogens combine to cause cancer. For example, age may be one factor that has been identified. This is because advancing age allows for a series of changes in the body that can lead to the transformation of normal cells into cancerous ones. Risk factors are important in as much as they have the ability to affect genes responsible for normal cell functioning.
In dogs and other pets, risk factors like smoking and other items of human use are of little importance. Most of the factors that increase the risk of feline cancer and cancer in dogs can be classified under two categories:
* Carcinogens - viruses, chemicals and physical carcinogens that can be found in the environment
* There are certain DNA and RNA viruses, normally termed as tumor viruses that have the capacity to pass their own genetic information to the DNA of the cells they infect. It is a complex infection which may involve the virus turning into a cancer causing agent or merge partially with the infected cell.
* There are chemicals that may cause cancer directly or indirectly. Indirect carcinogens need enzymes present in the body to act as catalysts for them to turn carcinogenic. Direct carcinogens, however, are reactive compounds in their own right.
* Physical carcinogens include exposure to radiation: ionized or ultraviolet, fibers like asbestos, and hyperthermia.Genetic Disorders - inherited or acquired.
* A dog may inherit cells carrying genetic material from generation to generation. A gene that suppresses formation of a tumor may get inactivated. On the other hand a gene that causes normal cells to change into cancerous cells may get activated in the sperm or the ovum.
* In some cases cancerous cells develop during mitosis, the process of multiplication of cell by division and are not hereditary in nature. This is an instance of an acquired chromosomal defect where a parent cell passes on the genetic information to the daughter cells that it divides into.
Prediction of cancer is highly improbable. It is ultimately left to the correct reading of signs, such as symptoms of liver cancer in dogs, which can lead to an early detection of this fatal disease. Advancements in treatment therapies for cancer have resulted in many success stories of pet cancer treatment. If it is determined before metastasis affects vital organs, it is possible to extend the life of your dog as well as improve its quality for as long as he lives.
Monday, May 5, 2008
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