If you want to know how cancer grows, first you have to know that your whole body is made up of cells. They´re like the bricks of a house. The more bricks, the bigger the house. It is like that with the human body too, there are cells and little cells everywhere.
Because cells can divide – one cell becomes two, two become four, four become eight and so on – every day there are a lot more of them. Fortunately every day a lot of them die too, because otherwise you would have too many.
In cancer something goes wrong with those cells. One of the cells breaks up and gets ill. The poorly, bad cells divide and divide and keep on growing. Such a bad cell is called a cancer cell. They gather together, push the healthy cells away, can even grow right through everything and can wander around the body. Something has to be done to stop those cancer cells!
Cancer is a really terrible disease. Even so you often can´t tell from the outside that your mum or dad is that ill. That can sometimes be hard.