Oncogenes are often mentioned in the news in association with cancer. But, what are these oncogene things? A careful evaluation of the word can yield some answers. Many hospitals now have oncology departments, even veterinary hospitals such as the Veterinary Teaching Hospital at Colorado State University have such facilities, which deal with cancer. And the later part of the word, -gene, would imply some kind of genetic control. As we will see both the idea of cancer and genes play a part in understanding oncogenes.

An oncogene is a malevolent change in a proto-oncogene. This should be about as clear as mud but let's clarify. First, a proto-oncogene is a regular, functional, portion of the genome. Every one of us contains many proto-oncogenes, the things we usually refer to as genes. The gene can however be taken from its proper place and transformed into a place it should not be. When this change causes aberrant behavior the proto-oncogene is then called an oncogene.

Think if you will of a piece of thread and a climbing rope. They are both pieces of fabric used for holding together two objects. The former holds two pieces of fabric or leather while the later holds two objects such as a climber and a rock together. Neither can acceptably do the job of the other. Scarcely one person on the street would wear a shirt sewn with twenty-five pounds of climbing rope. How do these compare to oncogenes and proto oncogenes? Imagine if you will a climbing rope, somewhat abused with a frazzled end. Years of wear have worn the rope down to a few threads at this point. These threads present no hazard in their present position, but if they are picked up and moved just a few feet down the rope and reinserted they can cause many problems. Primarily the entire rope is now non-functional and has an overwhelming tendency to drop the person who hangs from it.

This is the process by which a proto-oncogene becomes an oncogene. But, what difference does this make? In cells an oncogene inserted in the appropriate place will cause them to reproduce rapidly and lose their sense of when they are getting overpopulated. These cells are now cancerous. It should be made clear that all cancers are not caused by oncogenes, other substances and environmental factors can produce the same effect in cells. Also, not all oncogenes cause cancer. They are mainly identified in this manner because of the tendency of a person to only go to the doctor when there is a problem. A through screening of the population of the world would likely find some oncogenes that don't cause cancer.