July 20, 2010  -- Shannon Tavarez, a talented 11-year-old, competed against thousands of other star-struck young girls to win the part of young Nala, Simba's feisty feline girlfriend in the Broadway production of "The Lion King."

Now, she is hoping to beat the odds once more and find a bone marrow donor to help her fight the leukemia that has not only derailed her seven-month-young career but now threatens her life.

"It's a great feeling, performing for people and being young Nala, because she's tough and I feel like that's who I am through this whole experience," said Shannon.

Tavarez, who lives in New York City and is part African American and part Hispanic, needs a bone marrow transplant from someone who is a genetic match.

Both groups are underrepresented in the registry of potential bone-marrow donors. According to the National Bone Marrow Program, of the 7 million Americans listed as donors, only 7 percent, or about 550,000, are African-American. Only 3 percent are Hispanic and 2 percent Asian.

The first of two drives held by the bone marrow registry DKMS at New York's St. Malachy's, the actor's chapel, and got nearly 400 people to sign up; another one is scheduled for July 23 at the Minskoff Theater in Times Square.

"But that's not enough," said Katarina Harf, DKMS executive vice president. "We need thousands."

Those who would like to become bone marrow donors, can go online to DKMS and sign up for a swab kit that will be sent in the mail.

Results are sent to a lab for genetic testing and if it's a match for anyone in the database, including Shannon, the donor receives a call.

"We know minorities are underrepresented and have more varied DNA," she said. "It's like finding a needle in a haystack, looking for your genetic twin."

Shannon has no siblings. Non-African American or non-Hispanic donors are not excluded, but the likelihood of a good match is significantly less, according to Harf.

Tavarez got the role in the popular musical after her first-ever open audition at the Apollo Theater in Harlem. She had never appeared in a professional production, only in school recitals and plays.

"She is young Simba's girlfriend," said her mother, Odiney Brown, who works for the City of New York as a contract analyst for the Human Resources Administration. "She's the feisty, fierce lion. She really fears nothing."

Shannon 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."

Leukemia Masked as Cold, Virus

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. "We go into the city every day now and we are actually practically living at the hospital."

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.

AML Leukemia is Aggressive, Rare

Shannon's type of cancer is one of the least common of childhood leukemias, though it is the most common form in adults, according to Dr. Barbara Asselin, assistant professor of pediatrics and oncology at Golisano Children's Hospital at the University of Rochester Medical Center.

"It is generally an aggressive disease that requires chemotherapy," she said. "The first hurdle is to see if we can achieve a remission in the bone marrow and don't see any more leukemia cells, which know can hide in the body. A good response to early therapy is a factor in a good prognosis."

A bone marrow transplant can also be part of the first line of therapy, she said, but doesn't mean an "absolute cure."

"The chances of getting into remission are less and an eventual cure is less [than other types of childhood leukemia], but I am always optimistic about a cure," said Asselin.

Shannon was hospitalized for two months, undergoing chemotherapy. She temporarily lost her hair but suffered no other side effects like nausea or loss of appetite. She gave her family a scare when she developed an IV line infection, but it later resolved.

Today, Shannon is back home, watching movies -- she loves "Mean Girls" -- connecting with friends on Facebook and making string bracelets.

"I am just thinking positive that I get through this," said Shannon, who has been promised she can return to her Broadway role when she recovers. "I am excited for when everything will go back to normal."

Her mother is hopeful that Shannon will be able to make it to fifth grade next January, if a bone marrow transplant is successful.

"She's an energetic, very intelligent and very articulate girl, full of life," said Brown. "She is always excited, always asking questions and has this infectious spirit and knows how to pull people in. They all fall in love with her. I know -- I am her mother -- but that's the thing with her."

But Brown said she has her days when she has trouble coping with the thought of losing her daughter.

"She's always looking to me to see my reaction," said Brown. "I have to be on with her. I have my days when I am not around her. I drive to work and am out of her sight when I have my moments and a break down, but around her I have to be strong."

Those who would like to become bone marrow donors, can go online to DKMS and sign up for a swab kit that will be sent in the mail.

Results are sent to a lab for genetic testing and if it's a match for anyone in the database, including Shannon, the donor receives a call.