Researchers at the University of Birmingham have discovered a genetic fingerprint that could transform how doctors treat some of the hardest-to-cure childhood cancers. The breakthrough, published in Clinical Cancer Research, identifies aneuploidy—a specific pattern of chromosome changes in tumor cells—as a reliable predictor of which children will benefit from a powerful DNA repair drug called a PARP inhibitor.
The finding matters because children with relapsed Ewing Sarcoma and other aggressive solid tumors face grim odds: survival drops below 30% once cancer has spread or returned. For the 66 young patients enrolled across the UK, France, the Netherlands, and Spain in the eSMART Trial, most had already fought their cancers multiple times. Among them were 36 with Ewing Sarcoma, plus children with osteosarcoma, neuroblastoma, rhabdomyosarcoma, medulloblastoma, and other sarcomas and central nervous system tumors where standard treatments have failed.
The researchers tested whether combining a low-dose chemotherapy drug called irinotecan with a PARP inhibitor—a type of therapy long used in certain adult cancers—could work in children. They initially hypothesized that tumors with specific faulty DNA repair genes, or Ewing Sarcoma itself, would predict which children would respond. That assumption turned out to be wrong.
Instead, the retrospective analysis revealed something unexpected. When researchers examined the genomes of the 12 patients whose tumors shrank or stabilized for six months or longer, they found a striking pattern: those with high aneuploidy scores were significantly more likely to benefit from the therapy. Patients whose tumors had lower aneuploidy scores—despite having the genetic changes researchers had initially suspected would matter—showed no response.
Dr. Louise Hopkins, Trial Management Team Leader at the Cancer Research UK Clinical Trials Unit, called it a breakthrough with immediate clinical potential. "The impact of this study lies in its potential to change how clinicians approach treatment for children with high-risk, relapsed cancers; clinicians may now be able to determine in advance whether advanced therapies—specifically PARP inhibitors—will be effective for a specific child." This precision matters enormously for families facing agonizing treatment decisions for children with cancers that have already resisted conventional care.
Dr. Susanne Gatz, Associate Clinical Professor in Pediatric Oncology at the University of Birmingham, emphasized the significance of identifying any predictive biomarker in childhood cancer. While PARP inhibitors are standard care for specific adult cancers with known genetic signatures, pediatric oncology has lacked such a clear roadmap. "Having identified a high aneuploidy score as a potential biomarker for benefit to DNA repair inhibitor trials in pediatric cancers could identify such a specific cancer group," she said, adding that more research is needed to understand why this chromosomal pattern predicts treatment response.
The next steps are clear but ambitious: researchers must validate whether aneuploidy works as a predictive marker across other DNA repair inhibitor trials in children, and understand the biological mechanism linking chromosome instability to treatment sensitivity. For now, this discovery offers something rare in childhood oncology—the possibility of matching the right advanced therapy to the right patient before treatment begins, sparing children from ineffective interventions and bringing personalized medicine closer to the children who need it most.