Steps towards malignancy
A healthy cell does not turn into a cancer cell overnight. Its behaviour gradually changes, a result of damage to between three and seven of the hundreds of genes that control cell growth, division and life span. First, the cell starts to grow and multiply. Over time, more changes may take place. The cell and its descendants may eventually become immortal, escape destruction by the body's defences, develop their own blood supply and invade the rest of body.
