Bieber cancer is virtually the same as having "Bieber fever", except it includes symptoms of having trouble breathing, spontaneous nosebleeds, muscle aches, indigestion and/or weightloss, all of which are caused from an unhealthy obsession with Justin Bieber. This fatal diseases is mostly common in young females in the United States.
"Hey man, you've been quiet all night, how about a beer?"
"Sorry bro, it's just that... my sister died a few days ago."
"Dear God, what happened?"
*starts crying* "Bieber cancer"