When Bieber Fever is so excessive, that there is no cure. Can be found in multiple girls aged 5-40.

Signs of Bieber Cancer are:
1. Knowing every single Justin Bieber song ever written
2. Constantly talking about him
3. Believing that he is in love with you
Unlike other cancers, Bieber Cancer is contagious.
If you or someone you know are showing signs of Bieber Cancer, please contact a medical professional.
Carol- "OMG I just bought this JB poster! He's sooooo hot! And his haircut is sooooo cute!"
Sawyer- "Wow, she has serious Bieber Fever."
John Michael- "Its worse. Its freaking Bieber Cancer."
by meisfreakinamazin March 6, 2011
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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"
by Moris the Dinosauris February 22, 2011
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