Andrew Sato was abandoned, abused and, until two years ago, hadn't been in a stable home for most of his life.

The teen was also very sick, as if his life wasn't hard enough.

But despite all that — or perhaps because of it — Sato had a quiet strength and a maturity rare for someone so young. He fought against his anger, against the urge to give up and against leukemia — the disease that took him Saturday morning.

"He taught me to become stronger," said Edrelina Gamata, who got legal guardianship of Sato last year after taking him into her home as a foster child in January 2006. "He taught me to be thankful for whatever you had in your hand."

Sato, 17, died at Kapi'olani Medical Center at Pali Momi after he stopped breathing at home. The teen inspired hundreds across the state last month when he was honored with an early graduation at 'Aiea High School, fulfilling a lifelong dream. In the weeks to follow, dozens of residents and groups came forward to offer their support to Sato with monetary and in-kind donations and praise.

The governor and mayor also named days after Sato.

On Friday, the day before he died, Sato made an appearance on the KHON 2 morning news show to thank people for their support, and then was whisked over to the Capitol to be honored by the state Senate with a proclamation.

David Louis, executive director of Heart Gallery Hawai'i, which helped organize the special graduation for Sato, said the teen had a way of letting people forget their own difficulties and cherish what they have.

"More than anything, he just gave me more energy to continue doing this work for these kids," he said.

Sato had a rough start to life.

His father died when he was very young. And at 8, shortly after being abandoned by his mother in a park, Sato was diagnosed with leukemia for the first time and started treatment. While he struggled with his disease, he also bounced from foster home to foster home.

In his early teens, when his cancer was in remission, he was adopted into an abusive family that would choke him and hit him, Louis said. Sato ran away and was placed in a group facility. At 15, he finally found a home with Gamata.

But his life would not be stable for long. In April 2006, his cancer was back. Three months later, after aggressive treatment, it was gone again. But the third time it returned, late last year, it was stronger than ever.

Doctors said his cancer was terminal, so he stopped treatment to preserve his quality of life. He told his foster mother in a frank conversation that he didn't want to be kept alive with machines or to be revived only to live in a coma.

Michael Tokioka, principal of 'Aiea High, said Sato's story has moved his fellow students — not to mention the community. Though Sato was forced to miss much of his senior year, the school conferred a rare honorary diploma upon the teenager as a way of recognizing his difficulties and his courage.

"It was really a learning experience about life for our students," Tokioka said.

Reach Mary Vorsino at mvorsino@honoluluadvertiser.com.