In children with cancer, genetic differences among tumour cells that make up an individual tumour may predict treatment outcome, reports a study published online this week in Nature Communications.

Research on adult cancers has revealed that genetic mutations differ among the cells within single primary tumours and between primary tumours and their metastases. How this diversity effects treatment response and progression has previously remained unclear and it was also uncertain whether this level of diversity was present in tumours from infants and children.

David Gisselsson and colleagues observed microdiversity (genetic diversity among cells in millimeter-sized tumor samples) in the tumours of seven children who had received chemotherapy. This indicates that childhood tumours are not genetically stable, as was previously believed.

The authors also showed that the presence of microdiversity could predict treatment outcome in children with a common type of kidney cancer, nephroblastoma. In a study of 44 children with this type of cancer, those without tumor microdiversity survived 100 percent of the time.