How do healthy cells become cancerous?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.
Why is cell growth a problem in cancer?
How long do cancer cells live for?
Every time a normal cell divides, the ends of its chromosomes become shorter. Once they have worn down, the cell dies and is replaced. Cancer cells cheat this system - they retain their long chromosomes by continually adding bits back on. This process allows cancer cells to live forever. Cells from Henrietta Lacks, an American woman who was diagnosed with cervical cancer in 1951, are still growing. They are used in research laboratories all over the world, many years following her death.