Cyndie French sinks into the soft, blue cushions of her sofa and reaches for her son Derek. He scowls back at her. He knows he's sick, that it's the reason he can no longer go to school, the reason his little sister had to leave their home, the reason the power company shut off the gas. And Derek's angry.

"Leave me alone," he growls at his mother, shifting away from her.

Cyndie, a single mother of five, sighs and begins massaging Derek's shiny scalp as his eyes start to close. She prays that everything will go smoothly today - it is, after all, one of the most important days of their lives.

Seven months ago, Derek was diagnosed with neuroblastoma, an aggressive cancer that starts in the nerve cells and has invaded his bones and internal organs. Today, doctors will punch a hole in his hip, trying to capture enough bone marrow to find out whether he's eligible for a potentially lifesaving blood stem cell transplant.

Derek is just 10 years old. He's a gangly boy who walks on his tiptoes, prefers his pants baggy and wears his high-top sneakers unzipped. He's all about Star Wars and video games, and not at all about the chemotherapy, radiation and CT scans that have defined his life since his diagnosis.

Cancer has changed him, his mother admits. When Derek's feeling good, he's soft-spoken and quick to share sweet treats with his brothers, tender and playful with his little sister and his mum. But lately, his pain and fear have become too much for him, and he erupts into uncontrollable tantrums.

Cyndie saves her tears for when Derek and her other children have gone to bed.

"I can't imagine what he's going through," she explains. "No-one can. But I won't cry in front of him. I have to be strong for him."

Cyndie wants to spare Derek the gruesome details of the bone marrow procedure. "They're going to put you to sleep, and when you wake up it will all be over and you'll feel better later," she tells him as they arrive at the hospital. But to Derek, the hospital represents misery, and soon his hands have curled into tight fists, signalling the onset of one of her beloved boy's meltdowns.

Luckily, as they enter a hallway leading to the waiting area, Cyndie spots salvation in the form of a wheelchair. "Get in," she urges Derek. She kicks off her suede thongs, grabs the handles of the chair and starts to push him down the mostly empty corridors. Faster and faster. Over and over. A worker manoeuvring a trolley clears her path and lifts his eyebrows in mock amazement. A pair of painters gives her a thumbs up. "Go, Mum!" Derek screams, squinting his eyes and lifting his arms in ecstasy. "Go! Go! Yesssssss!"

But this is a rare high point in Derek's short life. Over the next year - a harrowing year catalogued by photographer Renee Byer - he will endure countless operations and hospital stays. Meanwhile, his mother, Cyndie, will watch while her finances dwindle and the rest of her children suffer as she devotes all her attention to her sick boy.

YOU CAN MAKE A DIFFERENCE

By donating to this US charity, Derek's Wish, you will help provide financial aid to families fighting cancer. Simply visit www.dereks-wish.com.

Here in Australia, where thousands of children battle cancer every year, there are plenty of ways to help...

Donate: The Children's Cancer Institute Australia is working tirelessly to find cures for childhood cancers, including neuroblastoma. To donate, just visit www.ccia.org.au or call 1800 685 686. Your donation will help fund research that will make a difference to children like Derek.

Help at a camp: Camp Quality offers camps for children aged 4-18 living with cancer. To volunteer as a companion to a child for a camp once a year, please call (02) 9876 0500.

Volunteer: Get a group together and volunteer to cook a meal or help with housework at one of Australia's 12 Ronald McDonald Houses*, which provide accommodation for families with children in nearby hospitals. Visit www.rmhc.com.au.

Buy: Get your Christmas cards online from www.canteen.org.au, and $10,000 will go to CanTeen, which supports young people with cancer.