Mutational landscape of intracranial germ cell tumors.

Abstract

e14060 Background: Intracranial germ cell tumours (GCTs) are relatively rare tumours of the central nervous system, which account for 1% to 3% of cases. The pathogenesis of intracranial GCTs is unknown, molecular diagnostic methods currently play only a minor role in the diagnosis of CNS germ cell tumours, which generally rest on histopathological and secretory features. The objective of this study was to explore the molecular profile associated with Chinese intracranial GCT patients. Methods: This study retrospectively analyzed the genomic features of 24 intracranial GCT patients. Next-generation sequencing (NGS) of 551-gene panel was performed to detect gene mutations in tumor and blood samples of the patients. Results: The tumors originated most frequently in the pineal region (41.6%, 10/24), followed by the sellar tumor (16.6%, 4/24). The average age of the patients was 14 years (range, 4-55years), There is a male preponderance of 2:1. The most common mutation genes were KIT (4.23%, n=6), KRAS (2.82%, n=4) and PTEN (2.11%, n=3). KIT mutations are mainly missense mutations concentrated in exon 17, exon 11 and exon 13. Exon 2 and exon 3 of KRAS gene were the main mutation hotspots, mainly G12X(2.08%) missense mutation. The co-mutation of KIT and KRAS was only in one patient. Unexpectedly, four patients (16.6%) carried germline deleterious mutations, in FANCA(n=1), FANCD2(n=1), FANCE(n=1), SDHA(n=1). Two of the patients with germline mutations co-mutated with KIT and KRAS, respectively. Conclusions: 16.6% of the intracranial GCT patients carry germline deleterious mutations, and 12.5% in Fanconi anemia (FA) gene. Overall, these findings indicate that the Fanconi anemia (FA) pathway and the PI3K/AKT pathway play a significant role in intracranial GCTs tumorigenesis.