Question: why do we get brain tumours?

Joe Bathelt answered on 9 Nov 2016:

The brain is made up of different types of cells. Some of these cell types need to be replaced from time to time. In order to do this, they divide to create new cells. This is usually tightly regulated so that not more cells are created than necessary. However, on rare occasions, this process can go wrong. This means that some cells go rogue and stop listening to the signals that tell them to stop multiplying. Sometimes, this only takes up space, but in other cases, the cells multiply aggressively and over take important areas.