Surprising number of young cancer patients are predisposed to the disease

When cancer is found in a young patient, parents often ask: “Why my child?”

New evidence suggests that some children may be born at an increased risk of developing cancer early in life. In a landmark study from St. Jude and Washington University in St. Louis, investigators closely examined the genetic makeup of 1,120 children with cancer. They found that 8.5 percent—nearly one in 10—of those patients was born with genetic changes or mutations that increased their cancer risk.

These changes, called germline mutations, are found in the DNA of every cell, not just tumor cells. Such mutations were known to exist, but their frequency was a mystery.

“The study marks a turning point in our understanding of pediatric cancer risk and will likely change how patients are evaluated,” said James R. Downing, MD, St. Jude president and chief executive officer.

These mutations can be used to help guide treatment and advance precision medicine. In some cases, entire families may benefit from genetic testing and counseling. St. Jude is now offering comprehensive genetic testing to its patients as part of a clinical research study called Genomes for Kids. This study is designed to lay the groundwork for transforming childhood cancer therapy through advanced technology called genomic sequencing.

If a mutation associated with increased cancer risk is found, children and families are referred to the St. Jude Hereditary Cancer Predisposition Clinic. There, a team of medical specialists work with families to understand and better manage their cancer risks.

The study, part of the Pediatric Cancer Genome Project, was published in the New England Journal of Medicine.