Subtyping of Group 3/4 medulloblastoma as a potential prognostic biomarker among patients treated with reduced dose of craniospinal irradiation: a Japanese Pediatric Molecular Neuro-Oncology Group study.

BACKGROUND: One of the most significant challenges in patients with medulloblastoma is reducing the dose of craniospinal irradiation (CSI) to minimize neurological sequelae in survivors. Molecular characterization of patients receiving lower than standard dose of CSI therapy is important to facilitate further reduction of treatment burden. METHODS: We conducted DNA methylation analysis using an Illumina Methylation EPIC array to investigate molecular prognostic markers in 38 patients with medulloblastoma who were registered in the Japan Pediatric Molecular Neuro-Oncology Group and treated with reduced-dose CSI. RESULTS: Among the patients, 23 were classified as having a standard-risk and 15 as high-risk according to the classic classification based on tumor resection rate and presence of metastasis, respectively. The median follow-up period was 71.5 months (12.0-231.0). The median CSI dose was 18 Gy (15.0-24.0) in both groups, and 5 patients in the high-risk group received a CSI dose of 18.0 Gy. Molecular subgrouping revealed that the standard-risk cohort included 5 WNT, 2 SHH, and 16 Group 3/4 cases; all 15 patients in the high-risk cohort had Group 3/4 medulloblastoma. Among the patients with Group 3/4 medulloblastoma, 9 of the 31 Group 3/4 cases were subclassified as subclass II, III, and V, which were known to an association with poor prognosis according to the novel subtyping among the subgroups. Patients with poor prognostic subtype showed worse prognosis than that of others (5-year progression survival rate 90.4% vs. 22.2%; p < 0.0001). The result was replicated in the multivariate analysis (hazard ratio12.77, 95% confidence interval for hazard ratio 2.38-99.21, p value 0.0026 for progression-free survival, hazard ratio 5.02, 95% confidence interval for hazard ratio 1.03-29.11, p value 0.044 for overall survival). CONCLUSION: Although these findings require validation in a larger cohort, the present findings suggest that novel subtyping of Group 3/4 medulloblastoma may be a promising prognostic biomarker even among patients treated with lower-dose CSI than standard treatment.

Focal versus craniospinal radiation for disseminated atypical teratoid/rhabdoid tumor following favorable response to systemic therapy.

PURPOSE: Radiotherapy (RT) is associated with improved survival in atypical teratoid/rhabdoid tumor (ATRT); however, optimal RT delivery is unknown. A meta-analysis was conducted for disseminated (M+) ATRT receiving focal or craniospinal radiation (CSI). METHODS: After abstract screening, 25 studies (1995-2020) contained necessary patient, disease, and radiation treatment information (N = 96). All abstract, full text, and data capture were independently double-reviewed. The corresponding author was contacted for cases of insufficient information. Response to pre-radiation chemotherapy (N = 57) was categorized as complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). Univariate and multivariate statistics were performed to investigate survival correlation. Patients with M4 disease were excluded. RESULTS: The 2- and 4-year overall survival (OS) was 63.8% and 45.7%, respectively, with a median follow-up of 2 years (range 0.3-13.5). The median age was 2 years (range 0.2-19.5), and 96% received chemotherapy. On univariate analysis, gross total resection (GTR, p = .0007), pre-radiation chemotherapy response (p < .001), and high-dose chemotherapy with stem cell recuse (HDSCT, p = .002) correlated with survival. On multivariate analysis, pre-radiation chemotherapy response (p = .02) and GTR (p = .012) retained survival significance as compared to a trend for HDSCT (p = .072). Comparisons of focal RT (vs. CSI) and greater than or equal to 5400 cGy primary dose were nonsignificant. Following CR or PR, a statistical trend favored focal radiation (p = .089) over CSI. CONCLUSION: Chemotherapy response prior to RT and GTR correlated with improved survival on multivariate analysis for ATRT M+ receiving RT. No benefit was observed for CSI compared to focal RT among all patients and following favorable chemotherapy response, inviting further study of focal RT for ATRT M+.

Oncogenic FGFR1 mutation and amplification in common cellular origin in a composite tumor with neuroblastoma and pheochromocytoma.

Neuroblastoma (NB) and pheochromocytoma (PCC) are derived from neural crest cells (NCCs); however, composite tumors with NB and PCC are rare, and their underlying molecular mechanisms remain unknown. To address this issue, we performed exome and transcriptome sequencing with formalin-fixed paraffin-embedded (FFPE) samples from the NB, PCC, and mixed lesions in a patient with a composite tumor. Whole-exome sequencing revealed that most mutations (80%) were shared by all samples, indicating that NB and PCC evolved from the same clone. Notably, all samples harbored both mutation and focal amplification in the FGFR1 oncogene, resulting in an extraordinarily high expression, likely to be the main driver of this tumor. Transcriptome sequencing revealed undifferentiated expression profiles for the NB lesions. Considering that a metastatic lesion was also composite, most likely, the primitive founding lesions should differentiate into both NB and PCC. This is the first reported case with composite-NB and PCC genetically proven to harbor an oncogenic FGFR1 alteration of a common cellular origin.

The Japan Society for Neuro-Oncology guideline on the diagnosis and treatment of central nervous system germ cell tumors.

Primary CNS germ cell tumors (GCTs) are rare neoplasms predominantly observed in the pediatric and young adult populations. In line with the hypothesis that the primordial germ cell is the cell-of-origin, histopathological examinations for this pathology involve a diverse range of components mirroring the embryogenic developmental dimensions. Chemotherapy and radiotherapy are the mainstays of treatment, with surgery having a limited role for diagnosis and debulking of residual tissue after treatment. While better management has been achieved over recent decades by modifying radiation coverage and selecting appropriate chemotherapy, standardization of treatment remains challenging, partly due to the low volume of cases encountered in each institution. As the incidence is higher in East Asia, including Japan, the Japan Society for Neuro-Oncology established a multidisciplinary task force to create an evidence-based guideline for CNS GCTs. This guideline provides recommendations for multiple dimensions of clinical management for CNS GCTs, with particular focus on diagnostic measures including serum markers, treatment algorithms including surgery, radiotherapy, and chemotherapy, and under-investigated but important areas such as treatment for recurrent cases, long-term follow-up protocols, and long-term sequelae. This guideline serves the purpose of helping healthcare professionals keep up to date with current knowledge and standards of management for patients with this rare disease in daily clinical practice, as well as driving future translational and clinical research by recognizing unmet needs concerning this tumor.

Low tumor cell content predicts favorable prognosis in germinoma patients.

BACKGROUND: Germinoma preferentially occurs in pediatric and young adult age groups. Although they are responsive to treatment with chemotherapy and radiation, the treatment may cause long-term sequelae in their later lives. Here, we searched for clinical and histopathological features to predict the prognosis of germinoma and affect treatment response. METHODS: A total of 114 germinoma cases were included in the analysis. We investigated the association between clinical factors, tumor cell content, and progression-free survival (PFS). RESULTS: The tumor cell content was widely distributed from <5% to 90% in the specimens, with a median value of 50%. Female patients showed higher tumor cell content in the specimens (P = .002). Cases with lesions at atypical sites showed shorter PFS than those with lesions at other sites (P = .03). Patients with a higher tumor cell content (≥50%) showed shorter PFS than those with a lower tumor cell content (<50%) (P = .03). In multivariate analysis, tumor cell content was the only statistically significant prognostic factor (P = .04). Among the 7 cases treated with local radiation and chemotherapy, all 3 cases that recurred (2 outside of the radiation field, 1 unknown) had tumor cell content of ≥50% in the original specimen, whereas all 4 cases without recurrence had tumor cell contents of <50%. CONCLUSIONS: We found that tumor cell content significantly affected the prognosis of germinomas. Although validation of these results using an independent and larger cohort is necessary, this potentially opens the possibility of leveraging this pathological factor in future clinical trials when stratifying the treatment intensity.

Perfusable System Using Porous Collagen Gel Scaffold Actively Provides Fresh Culture Media to a Cultured 3D Tissue.

Culturing three-dimensional (3D) tissues with an appropriate microenvironment is a critical and fundamental technology in broad areas of cutting-edge bioengineering research. In addition, many technologies have engineered tissue functions. However, an effective system for transporting nutrients, waste, or oxygen to affect the functions of cell tissues has not been reported. In this study, we introduce a novel system that employs diffusion and convection to enhance transportation. To demonstrate the concept of the proposed system, three layers of normal human dermal fibroblast cell sheets are used as a model tissue, which is cultured on a general dish or porous collagen scaffold with perfusable channels for three days with and without the perfusion of culture media in the scaffold. The results show that the viability of the cell tissue was improved by the developed system. Furthermore, glucose consumption, lactate production, and oxygen transport to the tissues were increased, which might improve the viability of tissues. However, mechanical stress in the proposed system did not cause damage or unintentional functional changes in the cultured tissue. We believe that the introduced culturing system potentially suggests a novel standard for 3D cell cultures.

TERT promoter mutation status is necessary and sufficient to diagnose IDH-wildtype diffuse astrocytic glioma with molecular features of glioblastoma.

The Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) update 3 recommends that histologic grade II and III IDH-wildtype diffuse astrocytic gliomas that harbor EGFR amplification, the combination of whole chromosome 7 gain and whole chromosome 10 loss (7 + /10 -), or TERT promoter (pTERT) mutations should be considered as glioblastomas (GBM), World Health Organization grade IV. In this retrospective study, we examined the utility of molecular classification based on pTERT status and copy-number alterations (CNAs) in IDH-wildtype lower grade gliomas (LGGs, grade II, and III). The impact on survival was evaluated for the pTERT mutation and CNAs, including EGFR gain/amplification, PTEN loss, CDKN2A homozygous deletion, and PDGFRA gain/amplification. We analyzed 46 patients with IDH-wildtype/pTERT-mutant (mut) LGGs and 85 with IDH-wildtype/pTERT-wildtype LGGs. EGFR amplification and a combination of EGFR gain and PTEN loss (EGFR + /PTEN -) were significantly more frequent in pTERT-mut patients (p < 0.0001). Cox regression analysis showed that the pTERT mutation was a significant predictor of poor prognosis (hazard ratio [HR] 2.79, 95% confidence interval [CI] 1.55-4.89, p = 0.0008), but neither EGFR amplification nor EGFR + /PTEN - was an independent prognostic factor in IDH-wildtype LGGs. PDGFRA gain/amplification was a significant poor prognostic factor in IDH-wildtype/pTERT-wildtype LGGs (HR 2.44, 95% CI 1.09-5.27, p = 0.03, Cox regression analysis). The IDH-wildtype LGGs with either pTERT-mut or PDGFRA amplification were mostly clustered with GBM by DNA methylation analysis. Thus, our study suggests that analysis of pTERT mutation status is necessary and sufficient to diagnose IDH-wildtype diffuse astrocytic gliomas with molecular features of glioblastoma. The PDGFRA status may help further delineate IDH-wildtype/pTERT-wildtype LGGs. Methylation profiling showed that IDH-wildtype LGGs without molecular features of GBM were a heterogeneous group of tumors. Some of them did not fall into existing categories and had significantly better prognoses than those clustered with GBM.

Chemotherapy-induced autoimmune-mediated encephalitis during germinoma treatment.

BACKGROUND: Autoimmune mediated encephalitis (AME), which includes autoantibody-associated encephalitis and acute disseminated encephalomyelitis, is a common cause of encephalitis as well as infectious encephalitis in children. AME may be triggered by autoimmune responses to paraneoplastic syndromes and infections. Infectious encephalitis associated with an immunocompromised status caused by anti-cancer chemotherapy is well recognized; however, there have been few reports on the relationship between AME and chemotherapy. CASE REPORT: A ten-year-old previously healthy, developmentally normal girl was diagnosed with a pure germinoma in the suprasellar region. Following 30 days of induction chemotherapy, she developed a depressed level of consciousness with accompanying right hemiplegia, aphasia, and unexplained fever. Cerebrospinal fluid (CSF) analysis revealed positive oligoclonal bands and elevated neopterin levels. Neither atypical cells suggesting tumor exacerbation nor pathogens known to cause encephalitis were identified in the CSF. She was administrated immunosuppressive therapy and her symptoms rapidly improved. No known autoantibodies associated with autoantibody-associated encephalitis were identified in blood or CSF. However, the presence of oligoclonal bands and elevated neopterin levels in the CSF, and the favorable response to immunosuppressive therapy were consistent with an AME diagnosis. Thirteen days after the third course of chemotherapy, the patient developed a depressed level of consciousness again. Due to the recurrence of encephalitis, re-administration of immunosuppressive therapy was performed, which led to improvement in her symptoms. Recurrence of encephalitis has not occurred for 1 year after completion of chemotherapy. CONCLUSION: The chemotherapy-induced abnormal immune response might have triggered the AME.

[Gemcitabine and Docetaxel for the Treatment of Relapsed and Refractory Malignant Rhabdoid Tumor of Kidney and Atypical Teratoid Rhabdoid Tumor].

Gemcitabine and Docetaxel(GEM/DTX)are well known chemotherapeutic drugs for the treatment of soft tissue sarcomas. However, the efficacy of these drugs in the treatment of malignant rhabdoid tumors(MRTs)has not been well described. We used GEM/DTX as salvage chemotherapy for relapsed and refractory MRTs, including 2 patients with malignant rhabdoid tumor of the kidney(MRTK)and 2 with atypical teratoid rhabdoid tumor(ATRT). At the best, partial response was observed in 3 patients(2 MRTK and 1 ATRT). The remaining patient with ATRT had stable disease. Localized edema in the field of recent radiation therapy was discovered in 2 patients. In addition, one had pleural effusion without any evidence of tumor progression. GEM/DTX can be used as a potential chemotherapeutic drug for relapsed or refractory MRTs, although attention should be paid to its unique adverse events.

Monitoring Ponatinib in a Child with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia.

Ponatinib is a third-generation tyrosine kinase inhibitor (TKI) reported to show a higher efficacy for adult Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) than other TKIs. However, few studies describe ponatinib for pediatric Ph+ALL; therefore, the efficacy, safety, and optimal dosage have not been determined. Here, we report a 3-year-old girl with Ph+ALL treated by a ponatinib-containing regimen with therapeutic drug monitoring in the plasma and cerebrospinal fluid (CSF). In our case, a ponatinib-containing regimen was able to keep minimal residual disease negative, and the pharmacokinetics (PKs) of plasma ponatinib resembled that previously reported in adults. Penetration to the CSF was extremely limited. Thus, ponatinib was feasible and effective for a child with Ph+ALL, although the plasma concentration of ponatinib varied significantly throughout the treatment. The appropriate dosage should be confirmed in a prospective trial, including a detailed PK study.

Thiotepa-melphalan myeloablative therapy for high-risk neuroblastoma.

BACKGROUND: Appropriate high-dose chemotherapy (HDC) for high-risk neuroblastoma has not yet been established. In Japan, a unique HDC regimen that comprises two cycles of a total of 800 mg/m2 of thiotepa and a total of 280 mg/m2 of melphalan is widely utilized. METHODS: To evaluate the safety and efficacy of this thiotepa-melphalan high-dose therapy for high-risk neuroblastoma, we reviewed the medical records of 41 patients with high-risk neuroblastoma who underwent this regimen followed by autologous peripheral blood stem cell rescue between 2002 and 2012. MYCN-amplified high-risk neuroblastomas were observed in 23 patients. All patients underwent intensive multidrug induction chemotherapy, but none underwent anti-GD2 antibody immunotherapy. The primary tumor was resected at the adequate time point. RESULTS: The median follow-up duration for living patients was 9.2 years (range 5.5-14.0 years). The 5-year event-free survival (EFS) and overall survival from treatment initiation were 41.5 ± 7.7% and 56.1 ± 7.8%, respectively. The 5-year EFS of MYCN-amplified high-risk neuroblastoma patients was 60.9 ± 10.2%, which was significantly superior compared with those with MYCN-nonamplified high-risk neuroblastoma (16.7 ± 8.8%; p < .001). MYCN amplification was the most favorable prognostic factor for EFS (hazard ratio = 0.29; 95% confidence interval = 0.12-0.66). Of the 41 patients, three died because of regimen-related toxicity (infection, n = 2; microangiopathy, n = 1). CONCLUSION: The thiotepa-melphalan high-dose therapy with thiotepa and melphalan may be effective for high-risk neuroblastoma. However, this regimen is toxic and warrants special attention in clinical practice.

Topoisomerase IIß immunoreactivity (IR) co-localizes with neuronal marker-IR but not glial fibrillary acidic protein-IR in GLI3-positive medulloblastomas: an immunohistochemical analysis of 124 medulloblastomas from the Japan Children's Cancer Group.

We previously reported observing GLI3 in medulloblastomas expressing neuronal markers (NM) and/or glial fibrillary acidic protein (GFAP). Furthermore, patients with medulloblastomas expressing NM or GFAP tended to show favorable or poor prognosis, respectively. In the present study, we focused on the role of topoisomerase IIß (TOP2ß) as a possible regulator for neuronal differentiation in medulloblastomas and examined the pathological roles of GLI3, NM, GFAP, and TOP2ß expressions in a larger population. We divided 124 medulloblastomas into three groups (NM-/GFAP-, NM +/GFAP-, and GFAP +) based on their immunoreactivity (IR) against NM and GFAP. The relationship among GLI3, NM, GFAP, and TOP2ß was evaluated using fluorescent immunostaining and a publicly available single-cell RNA sequencing dataset. In total, 87, 30, and 7 medulloblastomas were classified as NM-/GFAP-, NM + /GFAP-, and GFAP +, and showed intermediate, good, and poor prognoses, respectively. GLI3-IR was frequently observed in NM +/GFAP- and GFAP + , and TOP2ß-IR was frequently observed only in NM +/GFAP- medulloblastomas. In fluorescent immunostaining, TOP2ß-IR was mostly co-localized with NeuN-IR but not with GFAP-IR. In single-cell RNA sequencing, TOP2ß expression was elevated in CMAS/DCX-positive, but not in GFAP-positive, cells. NM-IR and GFAP-IR are important for estimating the prognosis of patients with medulloblastoma; hence they should be assessed in clinical practice.

Rhabdoid tumor predisposition syndrome with renal tumor 10 years after brain tumor.

We report a case of rhabdoid tumor predisposition syndrome with a renal tumor developing 10 years after a brain tumor, which demonstrated an unexpectedly favorable outcome. A 2-year-old boy underwent gross total resection of a brain tumor located in the fourth ventricle, and received adjuvant chemotherapy and radiotherapy. At the age of 11 years, a renal tumor was found and nephrectomy was performed. He is currently alive without evidence of disease over 2 years without postoperative therapy. Histologically, rhabdoid cells were observed in both brain and renal tumors. Loss of SMARCB1 (also known as INI1) expression was found in the nucleus of both tumor cells. Genetic testing revealed pathogenic variants of SMARCB1 exon 5 in the renal tumor and SMARCB1 exon 9 in the brain tumor. In addition, heterozygous deletion of 22q11.21-q11.23 containing the SMARCB1 locus was shared by both tumors and this deletion was identified in normal peripheral blood. Considering the histopathological and genetic findings, our case was considered to be rhabdoid tumor predisposition syndrome with atypical teratoid/rhabdoid tumor and late-onset rhabdoid tumor of the kidney.

Drug screening with a novel tumor-derived cell line identified alternative therapeutic options for patients with atypical teratoid/rhabdoid tumor.

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare intracranial tumor occurring predominantly in young children. The prognosis is poor, and no effective treatment is currently available. To develop novel effective therapies, there is a need for experimental models for AT/RT. In this research, we established a cell line from a patient's AT/RT tissue (designated ATRT_OCGH) and performed drug screening using 164 FDA-approved anti-cancer agents, to identify candidates for therapeutic options. We found that bortezomib, a proteasome inhibitor, was among the agents for which the cell line showed high sensitivity, along with tyrosine kinase inhibitors, topoisomerase inhibitors, and histone deacetylase inhibitors, which are known to exert anti-AT/RT effects. Concomitant use of panobinostat potentiated the inhibitory effect of bortezomib on AT/RT cell proliferation. Our findings may provide a rationale for considering combination therapy of panobinostat and bortezomib for treatment of AT/RT.

TERT promoter mutation confers favorable prognosis regardless of 1p/19q status in adult diffuse gliomas with IDH1/2 mutations.

TERT promoter mutations are commonly associated with 1p/19q codeletion in IDH-mutated gliomas. However, whether these mutations have an impact on patient survival independent of 1p/19q codeletion is unknown. In this study, we investigated the impact of TERT promoter mutations on survival in IDH-mutated glioma cases. Detailed clinical information and molecular status data were collected for a cohort of 560 adult patients with IDH-mutated gliomas. Among these patients, 279 had both TERT promoter mutation and 1p/19q codeletion, while 30 had either TERT promoter mutation (n = 24) or 1p/19q codeletion (n = 6) alone. A univariable Cox proportional hazard analysis for survival using clinical and genetic factors indicated that a Karnofsky performance status score (KPS) of 90 or 100, WHO grade II or III, TERT promoter mutation, 1p/19q codeletion, radiation therapy, and extent of resection (90-100%) were associated with favorable prognosis (p < 0.05). A multivariable Cox regression model revealed that TERT promoter mutation had a significantly favorable prognostic impact (hazard ratio = 0.421, p = 0.049), while 1p/19q codeletion did not have a significant impact (hazard ratio = 0.648, p = 0.349). Analyses incorporating patient clinical and genetic information were further conducted to identify subgroups showing the favorable prognostic impact of TERT promoter mutation. Among the grade II-III glioma patients with a KPS score of 90 or 100, those with IDH-TERT co-mutation and intact 1p/19q (n = 17) showed significantly longer survival than those with IDH mutation, wild-type TERT, and intact 1p/19q (n = 185) (5-year overall survival, 94% and 77%, respectively; p = 0.032). Our results demonstrate that TERT promoter mutation predicts favorable prognosis independent of 1p/19q codeletion in IDH-mutated gliomas. Combined with its adverse effect on survival among IDH-wild glioma cases, the bivalent prognostic impact of TERT promoter mutation may help further refine the molecular diagnosis and prognostication of diffuse gliomas.