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Background Phase II clinical trial funded by Ministry of Health, Labour and Welfare from 1995 to 2003 evaluated efficacy of pathology-based three-group treatment stratification for CNS germ cell tumors (GCTs). We here present long-term follow-up results. Methods Total 228 cases were registered. Germinoma was treated with carboplatin+etoposide (CARE) and extended-local irradiation, local irradiation was added for intermediate-prognosis-group, and poor-prognosis-group was treated with ifosfamide+cisplatin+etoposide (ICE) and whole-brain or craniospinal irradiation. Results Mean/median ages at diagnosis were 16.8/16 years and female-to-male ratio was 40-188. Registry included 123 germinomas, 76 intermediate-prognosis-group cases (including 38 germinoma with STGC), 28 poor-prognosis-group cases and 1 mature teratoma. Median 222-months follow-up was conducted, and 56 recurrences and 39 deaths were recorded. 10 and 20-year recurrence-free survival (RFS) for germinoma, intermediate and poor-prognosis-groups were 84/79%, 83/76% and 59/59%, respectively, and overall survival (OS) for each were 97/91%, 92/85% and 57/53%, respectively. Prognosis for germinoma with or without STGC was the same. Basal ganglia germinoma showed significantly shorter RFS but OS was not different from other locations. Median age at death was 24 years, and ages were significantly different depending on causes, such as disease-related (14 years on average) and complications (29 years). OS after recurrence at 5/10/20 years were 64/62/48%.Hormonal supplementation was seen in 82% for neurohypophyseal cases and antidiuretic hormone supplementation was most frequent (82%). Among available cases, 20-out-of-155 cases showed neoplastic/vascular complications, among which cavernous malformation was the most (n=9). Median period until complication presentation was 235 months, and the rate at 20 years was 11%. Conclusions Germinoma and intermediate-prognosis-group cases showed long-term survival for approximately 90%, while more intensive treatment would be necessitated for poor-prognosis-group. Long-term survivors often required hormonal supplementation, and increasing frequency of treatment-related complications was observed. There is no end of outpatient follow-up for CNS GCT patients.

Introduction: Glioblastoma, IDH-wild type (GBM) is the most common malignant brain tumor with a dismal prognosis. Although its coding region is well-analyzed, little is yet known about the landscape of whole-genome in GBM. Here, we analyzed whole-genome sequencing data from large cohorts to completely uncover the genetic aberrations in GBM. Methods: We analyzed 281 whole-genome sequencing data of patients with GBM, of which 152 cases are from our cohort with deep coverage (×120) and 129 cases are from a public database. Results: The median numbers of somatic mutations and structural variants (SVs) per case are 3.0/Mb and 62.5, respectively. While a complex SV is rare in other malignant brain tumors such as IDH-mutant glioma (35% of samples), a large proportion of GBM cases (85%) have complex SV with ≥10 breakpoints. CDKN2A/B homozygous deletions (HDs) are usually comprised of a simple deletion in IDH-mutant glioma whereas about a quarter of CDKN2A/B HDs in GBM are induced by complex SVs. In addition, 30.5% of extrachromosomal DNA (ecDNA) involves multiple chromosomes. Taken together, complex SVs could play a key role in the initiation and progression of GBM. Our deep WGS enables us to delineate a fine view of clonal architecture, where mutational signature varies between clonal and subclonal mutations. The majority of clonal mutations consist of the clock-like signature, whereas subclonal mutations have a relatively low proportion of the clock-like signature. Instead, several other signatures including the APOBEC signature significantly increase in subclones, presuming that various mutational processes along with the clock-like signature contribute to the GBM pathogenesis in its progression phase. Conclusions: GBM evolves through exploiting complex structural variants involving multiple driver genes and the accumulation of genetic mutations caused by distinct mechanisms depending on its developmental stage.

Introduction Recent large-scale sequencing projects for IDH-mutant adult-type diffuse glioma (Astrocytoma, IDH-mutant and Oligodendroglioma, IDH-mutant and 1p/19q-codeleted) have revealed the genetic landscape of coding mutations. However, little is yet known about the non-coding regions and structural variants (SVs). We analyzed deep (> x120) whole-genome sequencing (WGS) to delineate the comprehensive genetic lesions of IDH-mutant gliomas. Methods We investigated WGS of 228 cases with IDH-mutant glioma (204 cases in our cohort along with 24 publically available cases). Results The median tumor mutational burden in astrocytoma and oligodendroglioma was 2.0/Mb and 1.7/Mb, respectively. The median number of SV per case was 15.0 and 4.5, respectively. SV was involved in known driver genes in 7.7% of cases, supporting a model in which accumulation of SV as well as mutation drives tumor initiation and/or progression. The distribution of SV is biased on each chromosome, suggesting that each chromosome has a distinct susceptibility for SV. In IDH-mutant astrocytoma, complex SVs are significantly enriched on chromosome 12 which frequently involves CDK4, suggesting that SVs could lead to tumor evolution. The numbers of SVs and single nucleotide variants (SNVs) per case are correlated, presuming that IDH-mutant glioma can progress by acquiring both SNV and SV in a time-dependent manner. Conclusion SV could contribute to the development of IDH-mutant gliomas as well as mutations. Since WGS has a great resolution for genetic alterations, further analysis would enable us to uncover glioma pathogenesis.

Diffuse intrinsic pontine glioma (DIPG) is surgically unresectable and one of the most devasting tumours in children. To date, there have been no effective chemotherapeutics against DIPG, despite a myriad of clinical trials. The intact blood-brain barrier (BBB) is partly responsible for the limited clinical response to chemotherapy. MRI-guided focused ultrasound (MRgFUS) is a promising non-invasive tissue ablation method for treating CNS tumours. Moreover, MRgFUS allows for temporary and repeatable BBB disruption. Our first objective was to determine the feasibility and safety of temporary BBB disruption within the brainstem using MRgFUS following intravenous administration of microbubbles in vivo. Our second objective was to select effective chemotherapeutics against DIPG cell lines, and to examine their therapeutic effects with MRgFUS in a murine model of DIPG which exhibits an intact BBB. Non-invasive opening of the BBB was determined in the brainstem of normal rodents using physiological monitoring and histological analysis. Doxorubicin was selected from a drug screen consisting of conventional chemotherapeutics tested against DIPG cell lines. We established SU-DIPG17 orthotopic xenografts which demonstrated diffusely infiltrative tumour growth. By LC-MS/MS analysis, MRgFUS led to a 4-fold increase in doxorubicin concentrations within the brainstem tumours as compared to controls. Moreover, the volumetric tumour growth rate was significantly suppressed in MRgFUS-treated animals, which also exhibited decreased Ki-67 expression. We demonstrated the feasibility and safety of MRgFUS in the rodent brainstem and have shown that MRgFUS increases doxorubicin uptake in the brainstem of a rodent model of DIPG. This preclinical data provides critical support for clinical trials investigating MRgFUS-mediated BBB opening, which may greatly improve chemotherapeutic efficacy against DIPG in children.