(medicalxpress.com) – Combined whole exome tumor and blood sequencing in pediatric cancer patients revealed mutations that could help explain the cause of cancer or have the potential to impact clinical cancer care in 40 percent of patients in a study led by researchers from Baylor College of Medicine and Texas Children’s Cancer Center.
The sequencing revealed unexpected findings in a number of patients, including mutations in genes not previously associated with the specific type of cancer that had been diagnosed, pointing toward the usefulness of broad-based testing of both tumor and blood samples for children diagnosed with solid tumors, say study senior co-authors Dr. Sharon Plon, professor pediatrics at Baylor, and Dr. Will Parsons, associate professor of pediatrics at Baylor and Texas Children’s Cancer Center.
The study, which appears in the current issue of JAMA Oncology, is part of the ongoing Baylor College of Medicine Advancing Sequencing in Childhood Cancer Care (BASIC3) project funded through a $6.6 million grant from the National Human Genome Research Institute and the National Cancer Institute.
More than 25 percent of patients in the study had a genetic mutation of potential clinical relevance detected in their tumor, including some that could guide selection of treatment in the event of tumor recurrence, reported Dr. Angshumoy Roy, assistant professor of pathology & immunology at Baylor and Texas Children’s Hospital and one of the study contributors. Nearly 10 percent had germline mutations in adult and pediatric cancer susceptibility genes that explained the cause of their cancer, and additional patients had mutations in genes that were related to risk of diseases other than cancer.
“Our findings were much broader than what we expected in both the tumor and the blood,” said Plon, who also is professor of molecular and human genetics at Baylor and director of the Cancer Genetics Clinical and Research Programs at Texas Children’s Hospital. “In a significant number of cases, results revealed mutations in genes that we would not even have thought of testing for, because they were not known to be associated with childhood cancer. These results suggest that using focused genetic testing could miss important findings.”