A Pioneer in Paediatric Oncology and Champion for Childhood Cancer Survivors.

It is with deep sadness that we mark the passing of Dr Mark E. Nesbit, Jr., a revered figure in paediatric oncology, a distinguished cancer researcher, and former SIOP President (1993-1995). Dr Nesbit’s career was defined by scientific vision, unrelenting dedication, and a profound compassion for children and families facing cancer. His legacy continues to shape the field, inspiring current and future generations of researchers and clinicians.

Dr Nesbit was among the first paediatric oncologists to focus on the long-term health outcomes of childhood cancer survivors—an area that has since become central to the field. As a faculty member at the University of Minnesota, he helped build one of the most respected paediatric haematology–oncology programmes in the United States.

His pioneering work in leukaemia biology significantly improved understanding of the disease and helped transform its prognosis—from a near-certain fatal diagnosis to a largely treatable condition. Dr Nesbit’s impact extended far beyond the lab, laying the foundation for safer, more effective therapies that continue to benefit young patients today.

He also emerged as a leading authority on Langerhans Cell Histiocytosis, contributing to the development of new treatment strategies for this rare condition. His multidisciplinary outlook drove innovative research that extended into other fields, including diabetes and multiple sclerosis—fostering collaboration across institutions and borders.

Dr Nesbit mentored over 50 paediatric haematologists during his career, many of whom have gone on to become leaders in their own right. He was known not only for his academic rigour but for his humility, generosity, and unwavering support of others. To those who worked alongside him, Dr Nesbit was more than a mentor—he was a trusted colleague, a source of inspiration, and a lifelong friend.

Dr Nesbit’s philosophy was rooted in the belief that childhood cancer research is not only a scientific mission but a personal one—driven by empathy, integrity, and hope. His life and legacy remind us that progress in paediatric oncology depends as much on compassion as it does on discovery.

SIOP joins the international paediatric oncology community in honouring Dr Mark Nesbit’s extraordinary life and contributions. We invite you to continue his legacy by supporting the next generation of researchers and clinicians. Learn more and contribute at: https://cure.childrenscancer.org/nesbit