A cancer-resistant mouse was discovered in 1999. It is not yet known why, but this mouse’s immune system hunted down and destroyed cancerous cells, pretty much irrespective of the type of cancer. The same trait was passed down to the mouse’s descendants, of which there currently are about 2000.
Not only that, but scientists have recently discovered that injecting white blood cells from resistant mice into ordinary cancer-infected mice cures their cancer. This is startling and exciting news: if we figure out how this is happening and develop a human analog for this process curing cancer — or getting permanently vaccinated against it — could be as simple as getting an injection of white blood cells.