Is a mutation just a faulty cell that then multiplies, can it be something else? Do you define a cancer because of

Question: Is a mutation just a faulty cell that then multiplies, can it be something else? Do you define a cancer because of where it is, the type of cell that was faulty or of any other reasons?

Asked by smularczyk to Mariam on 14 Jun 2010 in Categories: Your Research.
- Mariam Orme answered on 14 Jun 2010:
  
  Very good question, thank you!
  
  Every cell has a copy of your DNA in it. When a cell divides, it has to replicate the DNA, because one cell turns into two, and each one needs a copy of the DNA. Sometimes mistakes happen during this copying process, and the DNA gets changed slightly – that’s a mutation. When the mutant cell (in other words the cell with the changed DNA) divides, its DNA gets copied so the mutation gets passed on. So in short, a mutation always means that the DNA has been changed in some way.
  
  To answer your other question, yes, cancers are defined firstly by where they arise, so lung cancer always starts from cells in the lungs. But they can be sub-divided depending on what type of lung cell was faulty.
  
  Does that all make sense?

Question: Is a mutation just a faulty cell that then multiplies, can it be something else? Do you define a cancer because of where it is, the type of cell that was faulty or of any other reasons?