The diagnosis was certain. The boy had spitzoid melanoma, the most common form of the skin cancer in children. But the genetic change that launched the tumor was unknown. Until now.
Scientists used genomic testing and special tools to solve the mystery. The answer will help other children and even some adults with spitzoid melanoma.
The child was part of the St. Jude Genomes for Kids study. Scientists sequenced the DNA of his normal tissue and tumor. They also sequenced genetic material that gave them clues about differences in gene activity.
The findings led to a gene that formed when pieces of two genes broke and then fused. The fusion gene included part of the gene MAP3K8. The abnormal gene drove cell division.
One-third of children with spitzoid melanoma in this study had a fusion gene that included MAP3K8. The fusion gene was found in adults as well. The best news? Patients with the fusion gene may respond to precision medicines that are already available.
“Comprehensive clinical genomic testing was essential to find this initiating alteration. It shows the importance of comprehensive clinical genome sequencing,” said Jinghui Zhang, PhD, chair of St. Jude Computational Biology.
A report on this work appeared in Nature Medicine.