Question: why is there such a thing as cancer?

Fiona Hatch answered on 22 Mar 2012:

Cancer happens when your cells genes get mutated, meaning something goes wrong.

And the genes then tell the cell to divide and to keep dividing and growing. This is how cancer starts. If you can remove those cells early on, then thats okay. But if the cells start growing too much and starts spreading then this could kill.

Its sad to say but most likely cancer exists to try and keep the population down. If we had no illnesses or diseases then the population would just keep growing and take over everything and the world would not be able to cope with so many people.