Other genes determine the color of our eyes, tell injured tissues how to repair themselves and direct the female breasts to make milk after a baby is born. Most of the time these genes function properly and send the right messages. We remain in good health, with everything working as it should.
But there are an incredible number of genes and an unimaginable number of messages. And since the chromosomes reproduce themselves every time a cell divides, there are lots of opportunities for something to go wrong. Sometimes something does go wrong in the process of cell division—a mutation that alters one or more of the genes.
A cancer cell has an abnormal chromosome from genetic change or damage. The altered gene starts sending the wrong message or at least a message different from the one it should give. A cell begins to grow rapidly. It multiplies again and again until it forms a lump that's called a malignant tumor . Or cancer.
Uncontrolled Growth Rapid cell growth is not the same as malignancy. We all experience two normal situations in which our body tissues grow much more rapidly than they usually do. We grow from a single cell to a perfectly formed human being in nine months. Then we grow into a normal-sized adult human being over the next 16 years or so. As well, when we are injured and need rapid repair, restoration and replacement of damaged tissues, our bodies can produce many new cells in a very short time.
When either of these processes—growth or healing is completed, a set of genes tells the body that it is time to "switch off." We don't continue growing throughout our lives, and the scar we have after a cut has healed remains just that—a scar. Those are the rules.
