I remembered when I was young, people would often tell us that you have to be careful not to get infected by cancer. So be careful that their blood don't get into yours.
I told myself how absurd that they can think like this? What in the world were they thinking? How did they ever thought of such things?
And then this study came out, wherein they got the plasma of a cancer patient and they introduced it to "normal" cultured cells, and lo and behold, true enough, the cells transformed into cancer cells. They call it genometastasis.