A joke ,is a joke , something to laugh at , but cancer is deadly and often times the patients suffer " horribly ", nothing to laugh about!
Re. " French Fries ";Despite its name, the French fry is not French. The origins of the French fry have been traced back to Belgium, where historians claim potatoes were being fried in the late-1600s.
There are many references to "French Fries " by going to google, and there is absolutely no reference to the origin you mention [most likely an old wives tale]