I'd like to add an answer to the several good ones here to point out a slight distinction between the title and body of your question.
It's fairly common parlance to refer to stereotypes as myths, but there are certainly many myths which are certainly not stereotypes.
Consider the myth, or old wives' tale that:
Toast always lands buttered side down!
This would never be described as a 'toast stereotype', but it would be a myth. You could debunk, bust, or shed light on this myth - simply by dropping toast and watching it land buttered side up.
Next consider the stereotype, or at a stretch myth that:
Blonde-haired women are dumb.
A blonde-haired woman could break the stereotype, break the mold, prove herself, disprove the stereotype, by doing something intelligent I suppose.
A cliché is different again, and really doesn't fit at all here. I might use the cliché:
He's as old as the hills!
to describe someone, but he wouldn't really be busting a myth - and certainly not breaking a stereotype - in producing a birth certificate that proved himself younger than the hills.