Dave Sims and his identical twin brother Mark were always close. Inseparable in childhood, they spent their teenage years on hiking adventures together and looked forward to a happy, productive future – both dreamed of becoming doctors.

But in 2003, their carefree lives changed forever when Mark was diagnosed with melanoma. He was just 15 when his barber drew attention to a birthmark on his head – it had changed into a dark, raised lump. It turned out to be nodular melanoma, a type of skin cancer known for its tendency to spread, and two surgeries followed. But the prognosis was bleak. The family were told Mark had just a 50% chance of surviving five years.

“Luckily, Mark was a very positive person who just got on with life,” says Dave, now an emergency medicine consultant. “We both went on to medical school, and Mark never let that initial diagnosis define him – he passed that five-year mark, graduated and continued to lead a happy, healthy life.”

But in January 2015, Mark developed a cough and abdominal pain while working as a junior doctor. Just before his 27th birthday, scans showed the melanoma had spread to his liver, lungs and spleen. “We were absolutely destroyed,” says Dave. “Both being doctors, we knew the implications and that Mark would probably die. It was a terrible time for our family.

“But then we discovered how much melanoma treatment had moved on in the 12 years since Mark’s first diagnosis. His doctors first thought he might die within weeks, but after giving him a new targeted cancer drug, he quickly felt much better.’’

More time thanks to research

Mark had an increased risk of developing melanoma due to having a mutation in a gene called BRAF. We co-funded research that identified and characterised BRAF mutations in cancer and paved the way for industry to develop BRAF-targeting treatments like dabrafenib, which Mark received. Today, more than 8 in 10 people who receive cancer drugs in the UK receive a drug we helped develop *, often giving them more time with the people they love.

“The benefits lasted a year, then immunotherapy worked for a while. We got nearly two extra years with Mark, and he achieved so much in that time. He went back to work, fell in love, got engaged and was best man at my wedding – something that meant so much to both of us,” says Dave.

“Mark was determined to do whatever he could to help others, fundraising for Cancer Research UK and achieving his target of raising £100,000 a few weeks before he died.

That extra time was invaluable. It gave us special memories and a better sense of closure – and we have the advances in treatment to thank for that.”

Finding PEACE

Mark received treatment at the Royal Marsden NHS Trust. Around six months before he died, Mark learnt about our pioneering PEACE study (Posthumous Evaluation of Advanced Cancer Environment). This project invites people with advanced cancer to give informed consent for tissue samples to be collected before and after their death. These donations enable the PEACE team to study how cancer spreads and why treatments stop working in the final stages of cancer

Professor Samra Turajlic led the melanoma team at the Marsden and supported patients like Mark to take part in the study. Her lab’s subsequent work at the Francis Crick Institute identified key aspects of how melanomas evade immunotherapy by profoundly altering their own DNA, giving them many paths to resisting treatment. But it didn’t stop there. The PEACE study has since provided even more insights.

All in the genes

One finding relates to the ability of melanoma to lose genes necessary for immunotherapy to work. The role genes play is of particular interest to Dave, as his family is genetically predisposed to the disease – several of them have successfully had melanomas surgically removed, including him.

The PEACE study results present the most detailed picture yet of what melanoma looks like genetically in the final stages of life and could pave the way for more targeted treatments in future.

“Evidence shows that immunotherapy could be a transformational treatment for up to half of people diagnosed with advanced melanoma,” says Professor Turajlic, now director of the Cancer Research UK Manchester Institute. “However, for the remaining 50 per cent, we urgently need to understand why treatments don’t always work. The PEACE study provides a unique opportunity to do so, because of the ability to study tumours throughout the body and piece together the puzzle of their evolution. We as clinical and research teams are extremely humbled by the willingness of patients and families to consider research at such a difficult time, and we honour their commitment by conducting meaningful work in the PEACE programme.”

For Mark, there was no hesitation when he was asked to donate samples. “There was no question,” says Dave. “He was so grateful for the advances that allowed him to extend his life and the people who made that happen. And by then, his main focus was reducing the risk of skin cancer for others.”

Mark died on 19 January 2017, aged 28, surrounded by his family and friends. “Everyone wants to feel that their life has meaning and taking part in the PEACE study definitely gave Mark an extra sense of purpose,” says Dave. “He may have had a relatively short life, but he achieved so much and made a huge contribution to the world. I’m so proud of what Mark did.”

^{*Estimated based on Cancer Research UK analysis of England data}

This article was adapted from an original piece published by Telegraph Media Group as part of a partnership to promote our skin cancer research. You can read the original version on their website.