HER love for her best friend is the driving force behind Grace McGregor's determination to help beat cancer.
Grace met Sarah Buitelaar when they were in their first year of primary school, by which time Sarah's dad was desperately ill with bowel cancer.
Her father, Frans, had fallen ill on a business trip to Scotland and, as he was too ill to travel home for treatment, the whole family moved north.
Grace, now 22, and Sarah became fast friends - and Sarah's experience has influenced Grace's life choices.
Cancer scientist Grace said: “Sarah and I met in primary school when we were five. When she was six, her dad died of cancer and that was my first ever experience of the disease.
"But when you’re so young, you don’t realise the reality and the impact of cancer.
“It’s only as we’ve grown up together that I realised that I have something Sarah will never have and that breaks my heart.
"When you think about big life events, my dad will be there and hers won’t - and why’s that fair?”
She added: “I wanted to do something to make a difference. I’ve seen the impact cancer has on families and I thought if there’s anything I can do to change that, then that’s what I’m going to do.”
Frans was diagnosed with bowel cancer in 2001 after being admitted to Ross Hall Hospital in Glasgow.
He was too ill to travel home to Lincolnshire for treatment, so Sarah’s mum moved the whole family from Lincoln to Alloway, Ayr, to be at his side.
Five year old Sarah was enrolled into primary one at Alloway Primary School where she met Grace.
PhD student Grace is a scientist at Glasgow's Cancer Research UK Beatson Institute, where she is studying how pancreatic cancer cells use energy in a different way to healthy cells in order to survive.
Her hope is that identifying a difference in how the cancer cells behave could lead to a new target for cancer drugs and better, kinder treatments for pancreatic cancer.
Inspired by Grace’s fight to beat cancer in the lab, Sarah decided to enter this year’s London Marathon to raise money for Cancer Research UK - and encouraged her best friend to enter with her.
But in the end, only Grace won a place in the ballot.
Spurred on by Sarah, her family and colleagues at the Cancer Research UK Beatson Institute, Grace trained hard through the winter months, building up her distance on runs along the Forth & Clyde Canal.
On Sunday April 23, she finished the marathon in three hours 50 minutes, raising more than £2100 for the charity.
Best friend Sarah, Grace’s mum and dad, and her close friend Helena were there to cheer her on through the streets of London to the end.
Grace said: “When I crossed the finish line, I felt totally overwhelmed. I felt a huge sense of relief that I’d actually done it, but also a huge sense of accomplishment.
“It really hit home in the last few miles that I’d done something so big, that people weren’t just sponsoring me to run, but what I’ve devoted my life to doing - my research.”
Grace is now pulling on her trainers once again to encourage people from all walks of life to enter the Race for Life 5K, 10K and Family 5K events at Glasgow Green on Sunday.
She wants to highlight the crucial connection between taking part and helping save lives by funding vital work into the prevention, diagnosis and treatment of the disease.
She said: “It doesn’t matter if you walk, jog, run or hula hoop your way round the course - by taking part in Race For Life, people in Glasgow can make a real difference in our fight against cancer.
“Researchers like me are using the money raised to really make an impact in the fight against the disease and drive the research forward.
“Every penny counts. I’ve seen in the lab the impact that it has and the difference we can make to beat cancer sooner.”
As first told in the Evening Times, this year's Race For Life - on Sunday - includes a Family 5k that allows men to take part too.
Last year, around 37,612 people took part in Race for Life in Scotland and raised almost £2.5 million.
Glasgow has been chosen to host one of the new Race for Life Family 5K events.
While the traditional women-only Race for Life Glasgow 5K and 10K events start at 9.30 am, an hour later at 10.30am men, women and children will be able to take part together in the new Family 5K.
Victoria Steven, Cancer Research UK spokeswoman in Scotland, said: “By taking part in Race for Life, Scots can make a real difference in the fight against cancer.
“One in two people in the UK will be diagnosed with cancer at some point in their lives. Research is very expensive and the only way we can afford to fund it is with the help of our supporters.
"Money raised through Race for Life is helping to drive life-saving research into over 200 different types of cancer – so every person, step and penny raised counts.
"We’re so grateful to all the people across Glasgow who walk, jog and run at Race for Life.
"Thanks to their participation, and commitment to raising the crucial funds needed to beat cancer, we can continue to make vital strides forward in research.
"The advances we’ve made since Race for Life started in 1994 show we are moving in the right direction.”
Sign up for Race for Life now at raceforlife.org or call 0300 123 0770.