It works by hunting down neuroblastoma cells that have survived conventional treatment and attaching antibodies to specific molecules on their surface.

BBC: Trial launched into neuroblastoma child cancer

Neuroblastoma is a cancer of specialised nerve cells, called neural crest cells.

BBC: NEWS | Health | Skin cells 'fight child cancer'

Since being diagnosed with neuroblastoma - a cancer of the nerve cells - Belle has been undergoing treatment at the Royal Marsden Hospital in Sutton as part of a clinical trial.

BBC: Alistair and Belle