Singer Alexandra Burke, the former X-Factor winner, launched the Cancer Research UK 5k event with Ben Magee, seven, and Adele O'Brien, 36 in Glasgow.
A total of 14,483 runners dressed in pink joined the run, the UK's biggest Race for Life event.
Ben was diagnosed with leukaemia in Spring 2011, a few months before he started primary school and has just received his final chemotherapy treatment at Glasgow's Yorkhill Hospital.
His mother Fiona, 47, from Rutherglen, South Lanarkshire, said her son was an "incredible wee boy".
She said: "He was diagnosed with leukaemia only a few months before he started school for the first time and he went through so much. But he started school bang on time, like all his friends, and has proved strong as an ox through it all.
"That's just the way he is and we are so proud of him."
She added: "The first couple of months were horrendous but hearing all the positive stories kept us going.
"I wanted to keep Ben at home and wrap him up in cotton wool but the nurses were fantastic. They said you can't let him be different from his friends. Let him get out there to live life and enjoy life. We've had amazing support from family, friends, teachers, doctors and nurses.
"That's why the Race for Life is so uplifting, it's every single one of us saying: 'One day we're going to beat cancer'. That is something to celebrate."
She recruited a "pink army" of around 30 friends to run with her at the Race for Life, cheered on by husband Gerry, 43, a former marketing manager with Scottish Power, and son Aidan, 11.
Adele O'Brien, from Old Kilpatrick, Lanarkshire, was bridesmaid at her sister's wedding the day after she was diagnosed with cervical cancer in July 2010 but kept the news from her family until after the event.
She said: "It was my sister's big day and I didn't want everyone to be miserable. So we just tried to put it to the back of our minds. We thought we could deal with it after the wedding.
"It was a beautiful day. We knew this bombshell was coming but we wanted to be happy for my sister."
She added: "It was an absolute nightmare. I was just devastated. I was so young and have two young children. I felt like I was fit and healthy at the time. I didn't really know anything about cervical cancer - only what I had heard about Jade Goody."
The mother, who has a nine-year-old daughter Eva and five-year-old son Logan, had chemotherapy, followed by surgery and radiotherapy and responded well after eight months of treatment and is celebrating three years in the clear.
Race for Life has already raised £526 million since it began in 1994. In 2014 Cancer Research UK hopes to raise over £50 million to help fund life-saving research into more than 200 types of cancer which affect men and women.
Last year, around 613,830 women took part in Race for Life at Glasgow Green and raised £858,000.
Claire Wase, Cancer Research UK's events manager for Glasgow, said: "We're so inspired by Ben, his mum Fiona and Adele and the bravery they have shown in the fight against cancer.
"We want to say a massive thank you to the generosity of the people of Glasgow who support Cancer Research UK by going the extra mile and making Glasgow the UK's biggest Race for Life."
Scottish Power has been the Official Energy Sponsor of Race for Life since 2012 and aims to raise £5 million over three years as part of a wider partnership with Cancer Research.