Cancer is a collection of more than 100 diseases having two major features in common:

  1. They are autonomous: Therefore, they cannot be regulated or controlled by the natural mechanisms the body has put in place to maintain equilibrium. As such, they are uncontrollable and display abnormal features and behaviors such as rapid growth.
  2. They are invasive or metastatic: This means they can migrate from the original site where they started to other parts of the body . Usually, in search of survival. Depending on the extent of migration, a cancerous cell can become incurable.
Because cancer is a collection of diseases,  you will hear different names such prostate cancer, breast cancer, lung cancer etc. Again, cancer cells can grow anywhere in the body. 

How does a Normal Cell Becomes a Cancer Cell?

The human body is made up of trillions of cells and each day at least 10 million of these cells die and need to be replaced. For example the cells in your skin need to be replaced after every 2 to 3 weeks. The body has therefore put in place a way or mechanism to control how cell grow and die naturally (apoptosis). This mechanism is under instructions from genes within your DNA. Therefore, anything that interferes with these instructions will cause normal cells to behave abnormally. Abnormal cell behavior will eventually lead to cancer.

Cancer therefore results from a sequential or progressive mutation overtime of essential genes that are responsible for maintaining a balance between cell growth and cell death. Because the body also fights back in trying to repair these mutations, carcinogenesis or the development of cancer is a slow process. It usually become successful when there is an accumulate damage to these genes such that the body finds it difficult to repair them anymore.

Cancer is hardly inherited although you can be genetically predisposed to it. By genetic predisposition we mean that you may have certain genetic diseases or characteristics that make you vulnerable under certain environmental conditions or lifestyle such as smoking.

Next: Causes and Prevention of Cancer