Riley Maclennan received the transplant in September 23 last year after the disease came back for a second time.
Riley, from Inverness underwent chemotherapy treatment and spent weeks in isolation in Glasgow - hundreds of miles away from home.
The youngster was just two-years-old when in December 2016, he was diagnosed with Acute Lymphoblastic Leukaemia, a cancer of the white blood cells.
He started on 28 days of intensive chemotherapy followed by regular chemotherapy over the next four years.
The family were told in October 2020 that Riley was in remission and he was able to ring the end of treatment bell at a ceremony at home in Inverness.
But Riley became unwell again and in May 15 he was diagnosed with myelodysplastic syndrome, a type of blood cancer that is very rare in children.
The family were told Riley’s best chance of recovery was a stem cell transplant, using stem cells from umbilical cord blood. After giving birth, some mothers choose to donate cord blood for transplant.
The donor’s healthy cells would reboot Riley’s immune system and hopefully stop cancer cells from growing again.
Riley had intense chemotherapy in an isolation room over 14 days before he was ready for the transplant at the Queen Elizabeth University Hospital in Glasgow.
It was administered into Riley’s bloodstream through a syringe. Now in remission, Riley and his parents Kevin Maclennan, 55, and Moira Black, 45, are sharing their remarkable family story to launch World Cancer Day in Scotland.
Proud dad Kevin said: “There’s a new mum out there who has saved our little boy’s life. We’ve been given the greatest gift of all from a stranger.
“The stem cells from the umbilical cord looked just like a small bag of blood but they had amazing power. Riley’s blood counts are great now and there are no signs of leukaemia cells. That means the world to us.
“Riley has an ability to bounce back and we’re so proud of him. We were told that Riley was the only child in Scotland who they’d seen this happen to after leukaemia treatment.
“They could find only one similar case in America and there were cases of two children who had been treated in London.
“After everything that Riley had been through we were devastated. Riley had grown up facing cancer and just as we finally thought we’d put that chapter of our lives behind us we were right back in it.”
They’re urging people to raise money for life-saving research by making a donation and wearing a Cancer Research UK Unity Band on February 4 - which as well as World Cancer Day also marks the charity’s 20th anniversary.
The band is available online and in Cancer Research UK shops in three different colours - pink, navy and blue.
It can be worn in memory of a loved one, to celebrate people who’ve overcome cancer or in support of those going through treatment.
Dad Kevin added: “There were so many hard parts of Riley’s treatment but the transplant in September was the chance of a new start.
“It was a gradual recovery in hospital but by November we received the best results possible when tests showed that Riley’s blood was 100 per cent donor so the transplant had worked.
“He’s loving being out of hospital. We’re home with Riley and can look forward to celebrating his eighth birthday in March.
“We owe all the staff at the Royal Hospital for Children in Glasgow a massive thank you. We’ve been through a lot as a family but now if we can help others we will.
“That’s why we want everyone across Scotland to get one of Cancer Research UK’s Unity Bands. Wearing one is such a simple way to show solidarity with people affected by cancer, while also raising vital funds.”
Lisa Adams, Cancer Research UK spokeswoman in Scotland, said: “As we mark our anniversary this World Cancer Day, we want to say a heartfelt thank you to Riley’s family for their incredible commitment to the cause.