Little Makaela Dancey has performed an adorable act of sisterly love by enduring painful surgery to help stop her sibling from suffering with the disease.
Keira Dancey, 13, had her life turned upside down when she was diagnosed with acute myeloid leukaemia in December 2017 - a rare cancer that affects only 3,100 people each year in the UK.
Following countless treatments to fight the aggressive illness, the teenager found out that she needed a life-saving bone marrow transplant.
And she was handed a remarkable lifeline from her sister Makaela, the only suitable donor in the family.
Her mum Emma, from Abbey Meads, Swindon, said: "She was very brave. She was the only match.
"She was scared. She first said she didn't want to do it. And I said to her that she could've pulled out at any time and no-one would be cross.
"We said to Makaela that Keira has been through a lot of operations and she has been okay. It's like a long sleep and you won't know anything about it.
"We also said that she could take her favourite toy that she takes everywhere still for comfort. She was happy with that.
"Keira is in remission at the moment. It is not guaranteed because she can relapse within the next couple of years."
The one-and-a-half-hour surgery was carried out at Bristol Children's Hospital last May.
Makaela said: "I did it because Keira needs it to get better, but it was painful."
Keira had multiplication complications over the past two years, going back and forth to BCH.
Emma remembers the day she found her daughter sick in her bed.
She said: "She was unresponsive and I couldn't wake her up, so I called an ambulance and within two hours they found out she had leukaemia.
"We got transferred to Bristol and then they found she had bleed on the brain, which they didn't think she would survive."
She added: "But she had multiple complications last year, and she was in intensive care with cardiomyopathy, which is a side effect of chemo.
"Her heart is coming back up to normal but it still slightly damaged.
"She finished treatment in May 2018, but we didn't get back home until the beginning of June last year."
In September, Keira returned to Abbey Park School before relapsing in February 2019.
Emma said: "We were getting our lives back to normal. But then she relapsed, so we had to go back to BCH to start chemotherapy again.
"The first round failed, she didn't go into remission, so they tried a new drug from America, which BCH hasn't used on children but had on adults."
Emma explained that didn't work but other drugs helped make Keira suitable for the bone marrow transplant.
The teenager is currently in isolation and is not allowed in crowded areas such as supermarkets or cinemas.
Keira said: "Being in isolation makes me feel bored and angry. I either stay at home or go to a friend's house as long as they haven't been ill."
Emma took on a sabbatical from her job as a support worker for adult workers with disabilities at Voyage Care. She will return in September, working two days per week.
She added: "Keira can't go out or go to shopping centre, which is hard for a 13-year-old specially during the summer holiday.
"Also, if people have been ill or are ill, they are not allowed near Keira either as infections will get her readmitted to hospital."
Keira will be home schooled from September until Christmas if there are no other complications.
She is still on weekly visits in hospital. During their time in Bristol, the family has been supported by charity CLIC Sargent.
Emma said: "They gave us as a family somewhere to take respite, wash our clothes. They have a playing room for the little ones and a gaming room for the teenager.
"It was also a place where to meet some families who are going through the same journey. And last year and this year we made life-long friends, people that we would not have met.
"The charity helped us tremendously over the last two years."
The 43-year-old is going to jump out a plane at Redlands Airfield tomorrow to raise funds for the charity.
She said: "I don't like heights, I don't like flying, but jumping out a plane is nothing compared to what Keira and other kids have to deal with."
She has already raised more than £1,000. To support them visit justgiving.com/fundraising/emma-dancey1 ENDS