Integrated Mutation Profiling and Prognostic Genomic Signature in Pediatric Testicular and Ovarian Germ Cell Tumors.

Background: Pediatric testicular and ovarian germ cell tumors generally have favorable outcomes, but a subset of patients experience relapse, progression, or persistent disease. Conventional risk assessment is based primarily on stage, histology, primary site, serum tumor markers, and treatment response; the incremental prognostic value of genomic profiling remains uncertain. Methods: This retrospective molecular clinicopathological study included 72 patients younger than 18 years with primary testicular or ovarian germ cell tumors diagnosed from January 2014 to December 2023. Pretreatment formalin-fixed paraffin-embedded (FFPE) tumor specimens underwent targeted next-generation sequencing with a custom 89-gene hybrid-capture panel. One qualifying feature was counted for each pathogenic or likely pathogenic Results: The cohort comprised 45 ovarian and 27 testicular tumors. Recurrent alterations included chromosome 12p gain; Conclusion: Targeted sequencing identified recurrent mutations and copy-number alterations in pediatric gonadal germ cell tumors. The exploratory adverse genomic signature was associated with EFS but not OS. This hypothesis-generating finding requires independent validation and does not establish mandatory testing, treatment escalation, or modification of first-line therapy.