SEATTLE – Research has proven that environmental factors like smoking or exposure to toxins can cause cancer in adults. But why and how children, even babies, get cancer, remains largely a mystery.

KING

While it's rare, cancer is the third leading cause of death in children today, after accidents, homicides and suicides. But tremendous strides have been made in the last 40 years, particularly in Seattle, in the treatment of pediatric leukemia. 

These breakthroughs are the result of a unique alliance of doctors at Children's Hospital and researchers at the Fred Hutchinson Cancer Research Center and the University of Washington.

Meet eight-year-old Max, who in the blink of an eye, went from rising star athlete to having one of the deadliest childhood cancers. He had a brain tumor the size of a golf ball. After surgery, he took part in a clinical trial that is changing the survival rates of children with brain tumors.

At just 21 months, Vinny was diagnosed with neuroblastoma, a cancer of the nervous system. It's a cancer that strikes just 600 to 700 children in the U.S. per year, but it is also the most common type of cancer in babies.

KING

Clinical trials have been key in curing some childhood cancers.

Vinny immediately entered into a national clinical trial that used a stronger chemotherapy in addition to a stem-cell transplant and radiation. Now five, Vinny just celebrated his third year anniversary of remission.

Bone cancer usually starts in the second decade of life, mostly teens, but it's also been seen in much younger children, even infants.  

Six-year old Haylee Hooper of Auburn was recently diagnosed with Ewing’s sarcoma, a rare bone cancer and has just begun an aggressive 10-month regimen of chemotherapy at Children's Hospital. Scientists at the Fred Hutchinson Cancer Research Center are analyzing Haylee's blood, and blood from 60 other sarcoma patients, to determine if genetics plays a role in how patients react to certain chemotherapy medicines.

Not all stories have been so promising. Travis Britt graduated from high school this past summer, but with the knowledge that he didn't have long to live. That didn't stop him from leaving behind a very inspiring legacy for his classmates and community.

The Mayo family, who lost 8-year-old Siri to cancer, have coped with tremendous support from their community of friends. To carry on her legacy, parent volunteers are creating a friendship garden at Siri's elementary school on Seattle’s Queen Anne Hill, that will include a sculpture of Siri's art.  

Read their stories and others below, and find out why doctors and scientists think the coming decades will bring great progress in cancer treatment.