Two Cancer Studies Find Bacterial Clue in Colon --The New York Times

Go to the  link in the headline to read the story. Whether this bug causes cancer or not, it is sobering to contemplate the means by which Fusobacterium, which is normally a denizen of the mouth, finds its way into the colon.

A Child Frolics in a Cancerous Colon. Found at the Kelly Laferty blog.