Whole genome sequencing to improve child cancer outcomes

Outcomes for child cancer patients could be dramatically improved by sequencing their genomes, a study has shown.

Researchers have shown that whole genome sequencing of child cancer patients can both improve the accuracy of their diagnosis, and better inform treatment options. Although only small-scale, the results demonstrate the capabilities of whole genome sequencing, which is set to be rolled out across England as the standard of care for all children with cancer.

'Whole genome sequencing can sometimes unravel unexpected results that may not have been considered via routine investigations,' explained Dr Patrick Tarpey, who led the study at the East Genomic Laboratory Hub, part of the Cambridge University Hospitals NHS Foundation Trust.

'Our results from this relatively small pilot group of children with cancer show how diagnosis and treatment can be improved,' he added.

Dr Tarpey presented the findings at the National Cancer Research Institute (NCRI) festival last week. Part of the wider 100,000 Genomes Project, the pilot study focused on 36 child cancer patients at Addenbrooke's Hospital, Cambridge, and encompassed 23 types of solid tumour. From each child both a blood sample and a tumour sample were taken for analysis. Sequencing of blood samples decoded the genome each child inherited from their parents, whereas sequencing of the tumour revealed specific mutations and variants present in the cancer. Investigation of both samples helped pinpoint the cause of tumours, as well as predict which treatments were likely to work best.

The patients' genomes were analysed with the help of an expert panel, called the Genomic Tumour Advisory Board. In six instances, whole genome sequencing led to a either a change or refinement of diagnosis. In eight cases, the child's prognosis was changed, whereas for seven children whole genome sequencing revealed a new treatment option which otherwise would not have been considered. In one particular case, a gene fusion was identified – where two genes had aberrantly joined together – that was likely driving tumour growth and could be targeted with a drug called a MEK inhibitor.

Whole genome sequencing has been made possible by Next Generation Sequencing (NGS) technology, which has increased the speed of DNA sequencing by more than a million-fold. NHS England is initiating whole genome sequencing as standard care for all children with cancer, in what is a major milestone for personalised medicine.

'Whole genome sequencing helps us to be more precise in tumour diagnosis and to tailor treatments to suit individual patients as accurately as possible,' commented Dr Julia Chisholm, chair of the NCRI Children's Group who was not involved in the research.

She added: 'As this innovation is introduced more widely, we hope that even more children will survive cancer.'