At 14, Hoel loved the mountains, science and baking. In September 2020, an Ewing sarcoma turned everything upside down. Hoel passed away in August 2022. Today, his father, Jean-Luc Célérié-Mangin, 54, runs, raises awareness and keeps his memory alive through the Marie Notre Étoile association, a partner of Imagine for Margo. His fight: to advance research so that one day, no child will have to leave their family because of cancer.
“Everything was going well”: the diagnosis that changed everything
Hoel was 14 years old. He had started complaining of mild stomach pain, especially at night. Nothing seemed particularly alarming at first. But when the family sought medical advice after the summer holidays in September 2020, the verdict was devastating: it was serious.
He was quickly referred to Institut Curie, where he was diagnosed with Ewing sarcoma. The standard treatment protocol followed: chemotherapy, surgery and radiotherapy. A treatment journey lasting around a year, which was expected to lead to recovery. However, Hoel already had metastases and, for this type of childhood cancer, there is still no truly effective treatment specifically adapted to this situation.
The family then tried other treatment protocols, including more innovative approaches. Some brought real periods of respite: a skiing trip, a week away, precious moments spent together as a family. But eventually, the side effects became more difficult than the benefits the treatments provided. Treatment had to be stopped. Hoel passed away in August 2022.
Mont Blanc: a family dream fulfilled
Before his illness, Hoel shared a passion for the mountains with his father and godfather. Three months before his diagnosis, they had climbed Mont Blanc du Tacul together, their first mountaineering summit. Mont Blanc was meant to be their next challenge.
During Hoel’s battle with cancer, the Rêves association made something extraordinary possible: a family helicopter flight around Mont Blanc. In the photo, Hoel’s smile says it all.
“In a way, being able to fulfil a dream was incredible. And experiencing it together as a family was exceptional. It is an unforgettable memory, something no one can ever take away from us.”
One year after Hoel passed away, Jean-Luc climbed to the summit of Mont Blanc with his son’s godfather. It was an ascent filled with mixed emotions: Hoel’s physical absence, but also the certainty that he was there with them.
“That climb helped me move towards something more positive and rebuild myself a little, like Notre-Dame, which took its time, which could have remained in ruins but is standing again today. We still have all our cracks, but we are here, and we are moving forward.”
Running for hope: discovering Imagine for Margo
Jean-Luc had been running for years, once or twice a week, and had already completed several half-marathons and marathons. But he used to run for himself, for the personal challenge. Hoel’s illness changed everything.
It was during his son’s battle that he discovered Imagine for Margo, which he describes as “a huge ray of hope”. The association funds research, brings together leading scientific teams in France and across Europe, and organises charity races. His first major fundraising challenge was the Institut Curie’s Course de la Jonquille in March 2022, which he completed as a marathon.
A few weeks later, he took part in Children Without Cancer for the first time. The emotional impact was immense.
“At that point, I was truly running for hope, for my son. Children Without Cancer is a magical race. There is such a strong sense of unity around the cause: the runners, the families, the children who are fighting, the memory of our children who have become stars. And the researchers are there too, leaving the event feeling re-energised. It is incredibly powerful.”
€25,000 raised = 6 months of research funded
When Hoel passed away, his family opened a fundraiser for Institut Curie. Thanks to the generosity of relatives, friends and colleagues, €25,000 was raised and donated to the research teams.
Through conversations with Hoel’s oncologist, Jean-Luc realised what that amount represented in practical terms: six months of funding for a researcher. It was a revelation.
“We understood that it was real, that it genuinely made a difference. And we discovered that researchers have to wear two hats: they are scientists, but they also have to manage teams, find funding, complete applications… all of which takes time away from the research itself. Imagine for Margo has this ability to break down barriers and simplify what is complex so that we can accelerate progress.”
Marie Notre Étoile: becoming a “booster” for Imagine for Margo
This year, Jean-Luc has strengthened his commitment by joining the Marie Notre Étoile association, which brings together around fifteen active volunteers, mainly in the Paris region — particularly Hauts-de-Seine and Yvelines — but also further afield.
“Imagine for Margo is the big rocket that knows where it is going, provides the framework, guarantees scientific excellence and ensures the proper use of funds. We, at Marie Notre Étoile, are a booster at our own level, but an important one. We work with local authorities and companies, take part in events and organise our own. Our goal is to raise awareness and funds for research.”
In 2024, Jean-Luc set himself a special challenge: running the 10 km “Marathon Pour Tous” during the Olympic Games. On his cap, alongside Hoel’s name, he carried the names of other children — some cured, some still fighting, some who had become stars.
“Children are our future. And what could be more important than taking care of our future?”
Childhood cancers: why research needs your support
Jean-Luc’s testimony highlights a reality that remains too little known. Childhood cancers still receive insufficient public attention, despite representing a major societal and public health challenge.
A few figures help put this into perspective:
- 2,500 children and adolescents are diagnosed with cancer every year in France.
- 30,000 children are affected across Europe.
- There are between 80 and 100 different types of childhood cancer, meaning these are rare and specific diseases that require dedicated research.
- The cure rate is now around 80%. This is encouraging, but it also means that one child in five still does not survive.
For many years, children with cancer were treated using chemotherapy originally developed for adults. Yet, as Jean-Luc points out, childhood cancers are fundamentally different from adult cancers: they appear very early in life, in young cells, and therefore require treatments specifically designed for children.
Today, public funding dedicated to childhood cancer research in France remains limited. Civil society therefore has a decisive role to play in scaling up research efforts. Imagine for Margo, together with its European partners involved in Fight Kids Cancer, funds major research programmes across Europe. But research needs to move faster: children cannot press pause while science catches up.
Go, Fight, Win: mobilising for a world without childhood cancer
When asked what Margo’s message — Go, Fight, Win — means to him, Jean-Luc answers without hesitation.
“Go means taking action, reacting. Fight means daring to face what will not be easy, and finding within yourself and around you the solutions and support you need. Win is the final result: changing things. It is a universal message.”
To those who are still unsure whether to get involved, his message is clear: everyone can take action, at their own level.
How you can take action with Imagine for Margo
- Make a donation, as an individual or a company, to directly fund childhood cancer research.
- Take part in charity races, particularly Children Without Cancer, to raise funds while sharing a powerful moment of unity with families, researchers and children.
- Raise awareness among your family, friends, colleagues or online community so that childhood cancers become a cause that is fully understood by everyone.
Jean-Luc also has one final message for families going through childhood cancer:
“Don’t be afraid. Find support. At the beginning, you are so caught up in the storm that accepting or asking for help is not easy. But there are associations that can support you, in addition to your family and friends. Don’t hesitate.”
Hoel loved life, curiosity and the mountains. His fighting spirit now accompanies every step his father takes. By supporting Imagine for Margo, you become part of this collective strength that advances research, accelerates discoveries and opens the way towards a cure for thousands of children.
→ Register for Children Without Cancer
→ Join the Imagine for Margo community
Article written by Maxime Roques, Communications Manager at Imagine for Margo