Shannon had attended Harlem School of the Arts for vocals and piano since the age of 3, and it was her coach who saw the notification for try-outs.
"I asked my mother if I could do it and she said, 'Sure, it will be fun,' said Shannon. "I didn't think that day that I would get it. There were thousands of kids."
The little girl made her debut in September 2009, playing four of the eight performances a week, alternating with another girl as understudy. She continued to attend public school.
"I loved meeting all the great people and having so much support from everyone and being on stage in costumes and running around with other kids," she said.
Shannon's contract was extended for six months and was supposed to be up in September of this year, but in April, she began to have unusual symptoms.
At first, Brown thought that Shannon's sniffles and coughing were a cold or a virus. Her pediatrician said she would be fine.
"But I started noticing she was very tired and fatigued and it wasn't normal," said Brown, 38. "She'd never been like that before. She looked peaked and that wasn't normal for her."
Shannon had trouble getting out of bed to go to school and later told her mother that keeping up with the "Lion King" was tough, too.
"She confessed to me that her legs and lower back were hurting while she was on stage and had to run up the stairs on the show," said Brown. "Then someone on the show said, 'Shannon needs rest, she seems tired.'"
Blood tests revealed that Shannon had acute myelogenous (AML) leukemia, a cancer of the bone marrow and blood.
"The day we found out, we immediately admitted our lives had just changed completely," said Brown.
Leukemia is a rapidly-progressing disease that results in the accumulation of immature, functionless cells in the marrow and blood, according to the Leukemia and Lymphoma Society. In many cases the bone marrow stops producing enough normal red cells, white cells and platelets. Anemia, a deficiency of red cells, develops in virtually all persons with leukemia.
Some 245,225 Americans are living with leukemia and an estimated 44,790 new cases are diagnosed in adults each year. Another 3,509 children up to the age of 14 get the disease each year.