By Stephanie Stahl

PHILADELPHIA (CBS) —  The doctors at the Children’s Hospital of Philadelphia save lives all the time, but the experimental treatment for one little girl has changed the face of cancer treatment.

She and her family went back today to say thank you with a big donation.

The Emily Whitehead Foundation donated $100,000 to CHOP’s Cancer Center.

This is where 10-year-old Emily became the first pediatric patient in the world to have an experimental immune-therapy treatment for acute lymphoblastic leukemia.

“We were just hoping for anything,” Emily’s mom said. “This was her last chance. This was the only thing she had left.”

Emily had relapsed twice when her parents decided to try the experimental treatment in 2012.

“A way of genetically engineering each patient’s immune system,” said Dr. Stephan Grupp. “So it can go back and kill its own cancer cell.”

“This is a brand new completely different and totally new way of treating cancer,” Dr. Grupp continued.

Dr. Stephan Grupp says the therapy has now been used to treat 80 children, and 93% are in remission, like Emily.

“It’s just amazing to me personally, to see her recover so quickly from her terrible disease,” said Dr. Grupp. “See how well she’s done.”

These days Emily is focused on her dog, Lucy, and school.

Technically still in remission, Emily continues to have signs of leukemia.

“They keep telling us that Emily is rewriting the history books,” Dr. Grupp said. “She was the first child in the world, with the immune system trained to beat her leukemia.”

With this donation, the Whiteheads hope other children can be saved with the money that they raised.

“Other than Emily having success, it’s one of the proudest times of my life,” said Emily’s dad.

The treatment called T-Cell Therapy, is still experimental, and is expected to be reviewed by the FDA later this year.

Doctors are also hoping it can be expanded to treat other cancers.

Stephanie Stahl