At Cardinal Glennon Children's Medical Center in St. Louis, the smallest patients sometimes need to be the bravest.
But there is a ray of sunshine for children on the fourth floor, and it comes in the form of 17-year-old Annamarie Persons.
"She takes all these kids and treats them like there her little siblings," said Jaclyn Fife, a mother of a young boy at the hospital who was recently diagnosed with leukemia.
Annamarie has been called the "Princess of the Fourth Floor."
"When he has all these people poking and prodding at him, she actually comes in and sits there with him," Fife said. "She makes him feel normal again."
It's nearly impossible to keep up with the high school junior from Fredricktown. Her positive attitude may be the most contagious thing in the hospital.
"She's always smiling and always trying to make everybody happy," oncology nurse Kim Whoberry said. "She never thinks about herself."
It wasn't always that way. Her mom says she was a typical teenager until last June, when she too was diagnosed with leukemia.
"A life-threatening illness with anybody is ‘Why me?' and that's what I thought," Annamarie said, "and now it's like well, ‘Why not me?'"
Make no mistake, Annamarie has had her moments. Her form of leukemia is a fast-growing cancer of the blood and bone marrow and requires intense chemotherapy.
"There's days when Anna doesn't even want to get out of bed but she does."
Annamarie believes that since getting healthy is the most important thing, then attitude is everything.
"I have a 50-50 chance either way and it's up to me. I have to be positive or negative about it. The more negative I am, than the less chance that I have."
Annamarie has been here so long, she celebrated the Fourth of July here, Labor Day, Thanksgiving, Christmas, New Years and now, she's celebrating her 17th birthday.
It seemed everybody on the fourth floor, at least the ones that could get out of bed, did, to celebrate Annamarie's birthday.
And she has another reason to celebrate. Her cancer is in remission.
"I started out the new year chemo free and cancer free," Annamarie said.
As soon as her immune system gets stronger, Annamarie will finally be able to go home.
Until then, she will continue to help the other children on the fourth floor by lighting their way on the road to recovery.