Question: Scientificaly, how would you explain cancer?

Rob Brass answered on 20 Jun 2016:

Hi!

Cancer happens when the DNA of a cell gets damaged and causes it to multiply and multiply and multiply and multiply … and a tumour forms.

The DNA is like the instruction manual of a cell, it determines how the cell behaves. It can get damaged by radiation (e.g. from the sun), chemicals (e.g. from smoking or drinking) or physical damage (a recent study says that drinking very hot drinks can give you oesophagus cancer!!). Most of the time the damaged cell will just die and another will replace it. No big deal, it happens all the time anyway – cells do something called ‘apoptosis’ which is basically cell suicide – between 50 and 70 billion cells die each day in the average adult.

Occasionally however, the DNA will become damaged in such a way as to cause the cell to keep multiplying, much faster than they normally would. This is dangerous for a couple of reasons: the first is that it creates a physical mass that is often inside an organ and so can affect how well that organ functions. The second is that the fast growing, fast multiplying cancer cells suck in a lot of nutrients that we need for other parts of the body and so can make you quite ill.