There is a large body of evidence proving that all the cells within a tumor mass are derived from a single cell. Imagine; one damaged cell can lead to a life-threatening tumor. The magnitude of the true meaning behind this is difficult to grasp because it is an extremely shocking and frightening revelation.

Even though all the cells within a tumor mass may be derived from a single cell, this does not mean that all the cells in a tumor are genetically identical like you might expect. Tumor cells are more unstable than normal cells, meaning they mutate at a much higher rate and they repair themselves much less effectively. Therefore, the cells within a tumor are different even from one another.

Fortunately, the chain of events leading to a single cell becoming a cancerous tumor consisting of millions of its offspring is a rare event. Actually, it is not just a single event that causes this, but several events that must occur in a specific sequence.

First, a piece of the DNA strand must be significantly mutated (we will talk about how this might happen later) and the mutations must slip through the repair mechanisms. These mutations may take place over generations of cells. For example, one generation may have one mutation; the next may not have any. A subsequent generation may have another and so on, until the