Say what you want about Justin Bieber. Just don't say it within earshot of 17-year-old Cassie Lorenz.
"Quit dissin' on my man, OK," she warns Dr. Paul Kelker as he cracked a joke about the teen pop star in the pediatric ward of the Billings Clinic on Tuesday.
He's comfortable throwing jabs her way -- he's gotten to know her very well over the past three years.
Cassie was diagnosed with rhabdomyosarcoma, cancer of the muscle, when she was 14, just weeks away from starting her freshman year of high school.
"I had fluids in my stomach that weren't supposed to be there," Cassie said. "They thought I had appendicitis, did a bone marrow test and that's how they found my cancer."
From the get-go, she was diagnosed at and continues to have Stage 4 cancer, despite countless chemotherapy treatments, six weeks of radiation and other experimental medications.
"She has been through an incredible amount of stuff," Kelker said. "More than anybody should have to go through, but we think the next phase we are doing shouldn't be nearly as nasty."
Cassie is scheduled for another round of treatment in January with a new experimental drug.
The prospect of new treatments doesn't seem to faze her — she's already been given a death sentence numerous times.
"I was told nine months ago that I only had three months to live," Cassie said.
"I'm still here."
After hearing the news, Cassie and her family went to Florida earlier this year as part of the Montana Hope Project.
Again exceeding the doctor's expectations, Cassie has narrowed her focus on a new dream: meet her idol, or as her friends call it, her obsession.
She owns practically every piece of merchandise with his face on it, and was sporting a purple Bieber T-shirt on Tuesday.
It's a love-hate relationship.
"I used to hate Justin Bieber, and I don't know what happened," Cassie said. "They say I'm obsessed. I guess it's because he's hot, I like his music and I don't know — he's my idol."
Cassie built up the courage and put herself out into cyberspace — much like her hero, she posted a video on YouTube and is hoping that Bieber will see it and grant her wish.
"I would do anything to meet him," she says through a sign in her video. "And I am gonna keep trying until it happens."
Just shy of 20,000 views, her friends are confident her dream will come true.
"I saw it on Facebook and I didn't think it would go that far, but apparently it did," said Trey Slates, Cassie's friend since fifth grade. "A lot of friends have shared it and done whatever they can to have Justin Bieber see it."
Her friends have just recently become strong supporters. When Cassie was first diagnosed, she relied mainly on her family.
"A lot of people didn't believe it," Trey said. "A lot of people thought Cassie was lying."
Cassie still goes to school from time to time and some of her classmates are still in the dark on her condition.
"A lot of people don't know I wear a wig or have cancer," Cassie said. "When I first went back to school, I told my friends I didn't want no special treatment.
"I didn't want to use the elevator anymore, but using the stairs was really hard."
Her classmates are now juniors, but Cassie is still a freshman by credits. Her job is to focus on the fight — especially next month.
"We plan to continue as long as she can stand it," Kelker said.