Precision Genomic Panels a Vital Clinical Support Tool in Pediatric Brain Tumors

A collaborative study conducted at various institutions in Boston, including the Dana-Farber Cancer Institute, Boston Children’s Hospital, and Harvard Medical School, has concluded that genomic assays can be successfully used to identify diagnostic, prognostic, and treatment-relevant alterations and can help guide precision treatment decisions for pediatric brain tumors.

The study authors firmly believe in the urgency of treating brain cancers in children. Despite progress in the field, the advances have not been dramatic, said co-lead author Pratiti Bandopadhayay, MBBS, PhD, in a press release. She also pointed out that existing therapies can have a long-term impact on cognitive and physical functions of the children.

The current trial used 2 genomic testing panels: OncoPanel, which sequences the exome, and OncoCopy, which examines the gene copy number and also defines rearrangement breakpoints. The prospective study examined the cancer genomes of 203 pediatric brain tumors across various histological sybtypes—117 samples were analyzed using OncoPanel, 146 with OncoCopy, and 60 samples were tested using both panels. Pathologists and cytogeneticists tested these panels in laboratories that were certified under Clinical Laboratory Improvement Amendments, commonly known as CLIA.

Exome sequencing using OncoPanel revealed clinically actionable alterations in 56% of patients (44 mutations and 20 rearrangements in cancer-causing genes). The list included BRAF, MYB-QKI, MYBL1, and FGFR1; BRAF is the most commonly mutated genes in pediatric brain tumors for which multiple targeted drugs are being developed, including dafrafenib (Tafinlar), which is approved as part of a combination regimen for advanced melanoma. Results of the combined analysis from the 2 panels identified subgroup-specific alterations in 89% of medulloblastomas, which constitute a fifth of all pediatric brain tumors.

Susan Chi, MD, another senior author on the study, said in the release, “Targeted therapies are likely to be most effective when they’re matched to specific abnormalities within tumor cells. Our findings show that precision medicine for pediatric brain tumors can now be a reality.” Chi is a pediatric hematologist/oncologist at Dana-Farber Cancer Institute.

Reference

Ramkissoon SH, Bandopadhayay P, Hwang J, et al. Clinical targeted exome-based sequencing in combination with genome-wide copy number profiling: precision medicine analysis of 203 pediatric brain tumors [published online January 19, 2017]. Neuro Oncol. doi: 10.1093/neuonc/now294.