On Monday this week The Conversation published a story under the headline
All the latest research points to the fact that the deadly DFTD is a transmissible cancer that originated in a female Tasmanian devil. A single cell in this devil (patient zero) developed into a cancer cell.
This is nothing unusual as cancers, whether they are devil or human, originate from a single cell. This single cell divided uncontrollably to produce a tumour (mass of cells).
DFTD developed mechanisms to avoid being killed by the devil’s immune system. Again, nothing unusual — cancer cells usually develop such strategies.
What is unusual about DFTD, though, is that it is transmitted between devils. The same cancer cells from patient zero have spread throughout most of the Tasmanian devil population, killing every devil infected — via redwolf.newsvine.com