CNS Germinoma Research Articles

QOL-28. NEUROCOGNITIVE DEFICITS, EMOTIONAL DISTURBANCES, PSYCHOSOMATIC COMPLAINS – ADDITIONAL SYMPTOMS OR COMORBID DIAGNOSIS IN CNS GERMINOMA? OVERVIEW OF GROUP AND CASE STUDIES

Abstract BACKGROUND CNS Germinoma cases are associated with good medical prognosis, low risk for neurological deficits and high cognitive functioning. Deeper psychological and neuropsychological examination and longitudinal observation shows also neurocognitive problems and emotional disturbances. The purpose of the study was to assess patients with CNS Germinoma (during and after anticancer treatment), expressed specific psychological and physical symptoms and to find the reason for this. METHODS Since 1998 all patients treated at our center are under psychological control and care. From these group 78 patients with CNS Germinoma with additional significant symptoms, seriously affected their quality of life and everyday activity, were selected for psychological and neuropsychological assessment. Age at psychological intervention ranged from 6 5/12 to 34 8/12 yrs. The patients have no pre-diagnosis history of neurological, developmental or psychiatric disorder. They were examined using a battery of standardized psychological and neuropsychological methods. RESULTS In our sample FIQ (full-scale intelligence quotient) score ranged from 59 to 139. The most patients presented average level of intelligence. However, cognitive functioning was often reduced due to emotional disturbances and psychosomatic complains. 2 patients showed memory disorders, one of them TGA (transient global amnesia) at the time of diagnosis. All patients struggled with emotional disturbances at different grades, especially internalizing type of problems (immaturity, depression, anxiety, instability, inhibition, negative attitude) or were considered to be at risk for psychological adjustment difficulties and tendency to somatization. Analyzed group of patients showed also social competences deficits. They may exhibit deficit in age-appropriate social competence and peers relations. CONCLUSIONS Although CNS Germinoma patients shows similar behavioral and emotional phenotype, there are significant differences between them in terms of cognitive functions. The range of results is wide, from high levels to neurocognitive disorders. Therefore, risk factors, diagnostic criteria and effective neuropsychological intervention, will also be presented and discussed.

GCT-29. MULTI-INSTITUTIONAL ANALYSIS OF PEDIATRIC RELAPSED/REFRACTORY CENTRAL NERVOUS SYSTEM GERMINOMAS

Abstract BACKGROUND Relapsed central nervous system germinomas are rare with no universal agreement regarding management. We explored the prognostic factors that may impact the treatment of patients with relapsed CNS germinoma. METHODS We collected data on relapsed/progressive germinomas from nine large international sites. Data was summarized using descriptive statistics. Overall survival (OS) was evaluated using Kaplan-Meier and Fischer’s exact test to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS Twenty-seven patients with relapsed (24) and progressive (3) germinomas were included (3.7% metastatic). Median age at diagnosis was 15.8 years (interquartile range (IQR): 11.9-18.5). Complete remission (CR) after initial treatment (chemotherapy 63.9% and radiotherapy 88.9%) was achieved in 15 patients (55.6%). The median time from diagnosis to relapse/progression was 20.0 months (range: 10.8-65.1 months) with 55.6% occurring within 24 months. Twenty-five patients (92.6%) underwent chemotherapy, 15 (55.6%) received high-dose chemotherapy with stem cell support (HDCx), and 16 received (59.3%) radiotherapy. At last follow-up, 86.6% of HDCx and 87.5% of radiotherapy recipients were alive. Median time to last follow-up was 41.8 months (IQR: 19.6-132.1). Fifteen children (55.6%) achieved CR after therapy and 21 (77.8%) were alive at last follow-up. Of patients receiving irradiation, 12.5% received whole ventricular irradiation, 81.3% craniospinal irradiation, and 6.3% focal irradiation. Chemotherapy at relapse was associated with improved 5-year OS (OR=1.32 95%CI: 1.06-1.64) Re-irradiation at relapse (OR=2.6, 95%CI: 0.36-19.2) and HDCx at relapse (OR=2.17, 95%CI: 0.30-15.71) did not reach statistically significant difference. CR after initial therapy (OR=1.25, 95%CI: 0.97-1.61) was not associated with improved 5-year OS, CR after relapse therapy was associated with increased 5-year OS (OR=3.50, 95%CI: 1.08-11.24) CONCLUSIONS Relapsed CNS germinomas are salvageable at relapse. This ongoing multi-institutional study will contribute to existing knowledge about relapsed/progressive CNS germinomas and inform prospective clinical trials to improve outcomes for children with relapsed/progressive disease.

GCT-18. GERMINOMAS OF THE CENTRAL NERVOUS SYSTEM (CNS): 20 YEARS EXPERIENCE WITH WHOLE VENTRICULAR IRRADIATION (WVI) AT FONDAZIONE IRCCS ISTITUTO NAZIONALE DEI TUMORI, MILAN

Abstract BACKGROUND Intracranial germ cell tumors account for 1-3% of pediatric CNS tumors, with germinomas constituting up to 65%, their prognosis being favourable compared to the non-germinomatous counterpart. METHODS After an unsuccessful experience with focal irradiation, from 2001 to 2021 we treated 68 patients (51 males/17 females, median age at diagnosis 16 years) with 4 PEB cycles (cisplatin 25 mg/sqm days 1-4, etoposide125 mg/sqm days 1-4, bleomycin 18 mg/sqm day 2, cycles every 21 days) followed by whole ventricular irradiation (WVI) 30,6 Gy/36Gy if CR/PR-SD. Patients with metastatic disease received craniospinal irradiation only (CSI 24 Gy+16Gy TB-tumor bed/WVI). RESULTS Fifty-nine patients had localized disease: 23 pineal, 22 suprasellar, 13 bifocal, 1 in the basal ganglia and 9 were metastatic. Suprasellar localization was associated with longer diagnostic delay. Five, 10 and 20 years OS and EFS were 100%, 97.5%, 97.5% and 95.3%, 92.8%.92.8% respectively. There was no statistical difference according to age at diagnosis, site and metastatic/bifocal disease. During follow-up 13/59 patients (22%) revealed moderate (2)/slight (11) impairment of the pulmonary function at spirometry assessment. Audiometric tests were available for 59 patients: 42 were normal (71%), 11 had a slight deficit, 4 moderate and 2 severe. Neurocognitive homogeneous evaluations were available only for 9 patients, so no clear correlation can be done, except observing the lowest scores in the patient with basal ganglia involvement. New endocrine deficits appeared in 9 patients after the treatment. CONCLUSIONS WVI tailored on response to chemotherapy proved effective in curing children CNS germinoma. Cisplatin and bleomycin-containing regimens induce high-response rates with known but in our experience limited sides effects. New collaborative protocols will investigate the reduction of the doses of irradiation and the use of less toxic drugs in order to achieve the same cure rates with less side effects.

OCT3/4 is a potential immunohistochemical biomarker for diagnosis and prognosis of primary intracranial germ cell tumors: a systematic review and meta-analysis.

Intracranial germ cell tumors (iGCTs), comprising of germinoma (GE) and non-germinomatous GCT (NGGCT), are a group of heterogenous brain tumors. Immunohistochemical markers, such as placental-like alkaline phosphatase (PLAP), are commonly used in diagnosis but show moderate sensitivity. Organic cation transporter 3/4 (OCT3/4) has been proposed as a novel biomarker for diagnosis and prognosis of iGCTs. This paper aimed to compare OCT3/4 with PLAP as potential immunohistochemical biomarkers in iGCTs diagnosis and clarify the relationship between OCT3/4 and prognosis of patients with iGCTs. Meta-analyses were performed to estimate pooled percentage point differences in positive rates between OCT3/4 and PLAP, their sensitivities, and correlation between OCT3/4 and prognosis in iGCTs. Nine articles were included representing of 241 patients. A fixed-effects model meta-analysis revealed that OCT3/4s positive rate was 8.6% higher (95% CI, 0.7% lower to 17.9% higher) than that of PLAP. Using fixed-effects models, sensitivities of OCT3/4 as a potential immunohistochemical biomarker in CNS GE and NGGCT were 85% (95% CI, 79% to 89%) and 56% (95% CI, 39% to 71%), respectively. In comparison, PLAP had lower sensitivities in both GE (73%; 95% CI, 64% to 91%) and NGGCT (43%; 95% CI, 27% to 61%). Moreover, OCT3/4 was significantly negatively correlated with 5-year progression free survival in patients with CNS GE (HR = 2.56, 95 % CI 1.47 to 4.44; p = 0.0008). Sensitivity analyses showed similar results. This study provides the first comprehensive assessment of the efficacies of OCT3/4 and PLAP in iGCTs detection and prognosis prediction, indicating OCT3/4 seems to be a more sensitive and reliable immunohistochemical marker in iGCT diagnosis.

RADT-36. MANAGEMENT OF PATIENTS WITH METASTATIC CENTRAL NERVOUS SYSTEM (CNS) GERMINOMA; A LITERATURE REVIEW

Abstract BACKGROUND No consensus exists on the optimal irradiation volume/dose for patients with metastatic CNS germinoma. We reviewed the literature for a potential association between different treatment modalities and survival. METHODS We searched PubMed for studies on patients with primary metastatic CNS germinoma including detailed survival outcome data. We used the Kaplan-Meier method to estimate event-free survival (EFS) rates and log-rank test for comparison among treatment modalities. RESULTS We identified 124 patients from 38 studies published between 1990 and 2021. The median age of presentation was 15 years (range: 1.5–47 years). Treatment modalities included: chemotherapy only (n = 5), radiotherapy only (n = 31), and radio-chemotherapy (n = 88). Radiotherapy modalities included: craniospinal irradiation (CSI) (n = 69), whole-brain irradiation (WBI) (n = 19), whole ventricular irradiation (WVI) (n=16), focal and spine irradiation (n = 5), focal irradiation only (n = 9), and not specified (n = 1). The median focal irradiation dose was 36.6 Gy (range:19.5-59.8 Gy). The median doses for CSI, WBI, and WVI were 24 Gy (range: 10.8-49 Gy). Eighteen patients relapsed, 111 were alive without disease, 2 were alive with disease, and 12 died of disease. The median follow-up time was 5 years in survivors. Four patients who received only chemotherapy relapsed. Five-year EFS rates were similar in patients who received chemo-radiotherapy and radiotherapy alone (89%, 95%CI 81-97%, vs 88%, 95%CI 74-100%, p = 0.6). Patients who were treated with CSI had a longer 5-year EFS compared to patients treated with other modalities (92%, 95%CI 84-100% vs 80%, 95%CI 64-94% p = 0.03). EFS was similar in patients treated with CSI whether they received ≥ 24 Gy or less. CONCLUSION CSI is required to achieve prolonged relapse-free survival (RFS). CSI dose of < 24 Gy may be sufficient to achieve sustained RFS. Future trials are needed to evaluate the potential role of neoadjuvant chemotherapy in reducing the dose/volume of irradiation in patients with metastatic CNS germinoma.

Evaluation of the Perioperative and Postoperative Course of Surgery for Pineal Germinoma in the SIOP CNS GCT 96 Trial.

Simple SummaryThere are many studies that discuss pineal tumors (not specifically germinoma). Some advocate for biopsy over resection due to the fact that germinoma is radio- and chemosensitive; others advocate for primary resection due to multiple differential diagnoses that require resection in the pineal region, such as pineocytoma, teratoma, meningioma, epidermoid, etc. However, with respect to solitary pineal germinoma, there is still no study that analyzes and compares both surgical options regarding peri- and postoperative courses and complications. We evaluated the perioperative course and postoperative complications of patients with isolated pineal germinoma who underwent a primary biopsy or resection, treated according to the European SIOP CNS GCT 96 trial. The key finding of our study was that postoperative complications, including hydrocephalus, Parinaud syndrome, double vision, etc., were significantly higher in patients who underwent primary resection (p < 0.008).Background: CNS germinoma, being marker-negative, are mainly diagnosed by histological examination. These tumors predominantly appear in the suprasellar and/or pineal region. In contrast to the suprasellar region, where biopsy is the standard procedure in case of a suspected germ-cell tumor to avoid mutilation to the endocrine structures, pineal tumors are more accessible to primary resection. We evaluated the perioperative course of patients with pineal germinoma who were diagnosed by primary biopsy or resection in the SIOP CNS GCT 96 trial. Methods: Overall, 235 patients had germinoma, with pineal localization in 113. The relationship between initial symptoms, tumor size, and postoperative complications was analyzed. Results: Of 111 evaluable patients, initial symptoms were headache (n = 98), hydrocephalus (n = 93), double vision (n = 62), Parinaud syndrome (n = 57), and papilledema (n = 44). There was no significant relationship between tumor size and primary symptoms. A total of 57 patients underwent primary resection and 54 underwent biopsy. Postoperative complications were reported in 43.2% of patients after resection and in 11.4% after biopsy (p < 0.008). Biopsy was significantly more commonly performed on larger tumors (p= 0.002). Conclusions: These results support the practice of biopsy over resection for histological confirmation of pineal germinoma.

The role of sex genotype in paediatric CNS tumour incidence and survival

PurposeEvidence exists, in CNS germinomas and medulloblastomas (MB), that patient sex significantly influences incidence and outcome. The role of sex genotype in other paediatric CNS tumours remains unclear. This study sought to examine the role of sex genotype in CNS tumour incidence and overall survival (OS).MethodsAge-adjusted incidence and OS rates were collected from the Surveillance Epidemiology and End Result (SEER) registry between 2000 and 2011 for common paediatric (<=19 years) CNS tumours: pilocytic astrocytoma (PA), anaplastic astrocytoma, glioblastoma (GBM), medulloblastoma, supratentorial CNS embryonal tumour, ependymoma, and germinoma. All patients with histologically confirmed, ICD-03 coded, first tumours, were included. Kaplan-Meier and Cox regression analyses were used to calculate hazard ratios (HR).ResultsThe total cases are as follows: males=3018 and females=2276. Highest incidence was seen in PA (n=2103). GBM displayed the worst OS, whilst PA displayed the best. Higher incidence was observed in males for all tumours, except PA. Females with ependymoma had significantly better OS compared to males, whereas males with germinomas had better OS compared to females. Females <1 year with AA had better OS than males. Increasing age significantly improved male and female survival in ependymoma and medulloblastoma.ConclusionInterrogating population-based registries such as SEER minimises bias and provides credible data. Observed differences in incidence and OS between the sexes for different paediatric CNS tumours provide useful prognostic information for clinicians. Sex genotype was a significant independent prognostic factor in ependymomas and germinomas. Further investigation of possible epigenetic and hormonal differences may provide sex-specific vulnerabilities that may be exploitable for targeted therapy.

Treatment outcomes in patients with central nervous system germinoma (neuro-ophthalmic aspects)

The analyze the neuro-ophthalmic outcomes in patients with pineal and suprasellar germinoma after complex treatment. There were 125 patients (88 males, 37 females) with primary CNS germinoma for the period 2008-2017. All patients were divided into 3 groups depending on the tumor localization: pineal area - 62 patients, suprasellar neoplasm - 38 patients, bifocal germinoma - 25 patients. Treatment was performed in accordance with the «Germinoma-2008» protocol. Tumors were histologically patients (partial - 32 cases, subtotal - 16 cases). Surgery was followed by postoperative chemotherapy and stereotactic radiotherapy. The results were evaluated by neuro-ophthalmological examination at all stages of complex treatment. Pineal germinoma resulted oculomotor and pupillary disorders (58 patients - 94%) and papilledema. The last one completely regressed under the treatment. Partial reduction of oculomotor and pupillary abnormalities occurred throughout chemotherapy (6 patients - 10%). More than half of patients (n=24, 63%) with suprasellar germinoma had visual impairment. Improvement of visual functions including severe visual disturbance was observed in 14 patients (58%). Predominantly, functional recovery occurred under chemotherapy (12 patients - 86%). Bifocal germinoma was followed by various combinations of oculomotor, pupillary and/or visual impairments. We observed regression of only mild visual disorders. Stereotactic radiotherapy did not ensure any changes in neuro-ophthalmic symptoms in all groups.

GCT-21. CENTRAL NERVOUS SYSTEM GERMINOMA - PONDERING THE NEXT STEPS

Central nervous system germinoma (CNS) represents one successful example where the introduction of chemotherapy into the treatment allowed significant and meaningful reductions in the volume and dose of radiation therapy while maintaining excellent outcomes. However, the long-term toxicities and morbidities of the current therapies, in addition to their substantial negative impact on the social wellbeing of germinoma patients, should clearly indicate that the current achievements are not enough. While stepwise cutback of the radiation therapy needs to be commended, real progress must be achieved in the exploration and investigation of biological and molecular markers. Furthermore, the differences that still exist between the several working groups around the globe in determining the tumor marker cut-offs that help diagnose these tumors illustrate their shortcomings, and therefore the need for newer and more reliable methods. Additionally, efforts should focus on the inclusion of metastatic and basal ganglia/thalamic germinomas in future prospective clinical trials given the lack of evidence on the best treatment strategy for these patients. A comprehensive review of all major CNS germinoma clinical trials will be presented aiming to lay a foundation for researchers and clinicians alike who are currently working on designing innovative approaches for this group of patients. This review also details the current issues of debate, and provides suggestions which may assist in the design of future prospective clinical trials for children with CNS germinomas.

GCT-20. EVALUATION OF NEURORADIOLOGICAL RESPONSE TO INDUCTION CHEMOTHERAPY FOR PATIENTS WITH LOCALISED GERMINOMA IN THE SIOP CNS GCT II TRIAL

INTRODUCTIONThe SIOP-CNS-GCT-96 trial demonstrated excellent survival for patients with germinoma. Localised patients received either craniospinal irradiation (CSI) 24Gy plus tumour-bed-boost 16 Gy or 2xcarboPEI chemotherapy (carboplatin/etoposide alternating with etoposide/ifosfamide) and focal-radiotherapy 40 Gy. Following trial closure, whole-ventricular-irradiation (WVI) was delivered with focal-radiotherapy to avoid ventricular relapse. Accordingly, current research priorities focus on reducing treatment burden and long-term neurocognitive sequelae.METHODSSIOP-CNS-GCT-II employed national central radiological review to assess whether dropping the 16Gy boost was safe for localized germinoma in complete-remission (CR) following 2xcarboPEI: i.e. no disease on clinical/marker/radiological assessment. Any abnormal thickening/enhancement after chemotherapy was to be classified as partial-remission (PR). Patients with less than CR after chemotherapy received a boost.RESULTSShortly before trial closure (2018), it was noted that national CR rates were discrepant across the largest recruiting countries. For German patients, CR rates were ~80%, compared with ~30–40% for UK and France. A formal neuroradiology review was therefore convened. A total of 59 cases were randomly selected (UK, n=32; France, n=14 and Germany, n=13), including those deemed to be in CR and PR. Cases included those with disease at pituitary, pineal and bifocal sites. Both diagnostic scan and scan after induction chemotherapy were used for assessment. Detailed analysis is ongoing and will be presented.CONCLUSIONResidual changes at both pituitary and pineal sites of uncertain significance may remain after chemotherapy. This process should facilitate consensus to define the best response criteria allowing treatment reduction for CNS germinoma for future clinical trials.

A Rare Case of Primary CNS Germinoma in the Pineal Region with Long-standing Hearing Loss

Germinomas in the brain are rare neoplasms which make up less than 1% of all intracranial tumors. Their clinical presentation is usually related to the increased intracranial pressure and/or hydrocephalus. This report describes a case who presented to our hospital for headaches and visual changes, including Parinaud's syndrome, that had started recently. The patient also had been complaining of chronic bilateral hearing loss for several years which seemed not properly evaluated previously. MRI brain showed a markedly enhancing lesion in the pineal region. CSF and serum tumor markers including B-human chorionic gonadotropin (B-HCG) and alfa-fetoprotein (AFP) were normal. Lumbar puncture with cytology was negative for malignancy. Biopsy was taken from the mass and sent to the pathology lab for testing. Histopathological examination showed changes consistent with germinoma and the immunohistochemical staining including that for placental alkaline phosphatase (PLAP) confirmed the diagnosis. There was no evidence of metastasis and the patient was treated with radiation-alone therapy that resulted in marked regression of the mass and significant clinical improvement except for the issue of hearing loss which had persisted, as expected, given its long-standing existance. In addition to highlighting the diagnostic evaluation and treatment approach for such rare tumors, this case suggests considering pineal germinomas among the differential diagnosis when dealing with hearing loss which needs careful evaluation and should never be underestimated.

RARE-03. CNS GERMINOMA WITH SYNCHRONOUS LESIONS IN THE SELLAR AND PINEAL REGIONS

Abstract Germinomas comprise approximately 2–5% of all CNS malignancies, and have a favourable prognosis. Bad outcomes are relatively rare. Synchronous lesions occurs in 5–10% of cases. We report a case of 28 years old male, presented with motor aphasia, visual impairment and dysphagia. In period of last 15 months patient underwent 3 surgical interventions due to occlusive hydrocephalus. MRI revealed volume formations of the pineal and sellar regions. Taking into account the severity of the patient’s condition, consilium decided to refrain from surgical intervention and adjuvant therapy. Patient was transferred to the palliative unit. He died after 3 months. According to the results of the autopsy, the histological changes in tumors of the pineal and infundibular regions, corresponds to the germinoma. Due to the lack of information about patient’s treatment, carried out until hospitalization in our center, we don’t undertake to judge whether there was diagnostic omission, or incorrect treatment in this clinical case. But in our opinion, in case of suspected CNS germinoma, it is necessary to conduct more “aggressive treatment” (Tumor biopsy, followed by radiotherapy and chemotherapy). Symptomatic treatment should be used in cases, where the treatment of main disease is impossible. We hope that this sad clinical case will help Neurosurgeons in making decisions in a difficult situation.

Clinico-pathological spectrum of Childhood Central Nervous System Tumors in Iraq: A Single-Institutional Study

Objectives: The present retrospective study analyzed the spectrum of pediatric CNS tumors in a single tertiary hospital in Iraq.&#x0D; Methods: Data regarding frequencies of various primary CNS tumors (diagnosed according to the World Health Organization (WHO) classification), in pediatric patients (&lt;18 yrs. of age), were collected from a single tertiary care hospital in Iraq for a period 2014-2017.&#x0D; Results: fifty-four children were diagnosed with primary CNS tumors. The most common primary pediatric CNS tumors were medulloblastoma (37%), followed by low grade gliomas (29.6%), high grade gliomas (0.011% ), CNS germinoma (0.09%), supratentorial primitive neuro-ectodermal tumors and ependymomas (0.037% for each). Rare tumors encountered were oligodendrogliomas, choroid plexus carcinoma, and pineoblastoma (0.18% for each). The most common low grade gliomas tumor was pilocytic astrocytoma.&#x0D; Conclusions: This is the first study reporting the spectrum of CNS tumors in children in Iraq. Except for a higher frequency of CNS germinoma, the profile of other pediatric CNS tumors in Iraq is relatively similar to that reported in other countries.

P05.56 Treatment algorithm of patients with primary CNS germinoma: the experience of N.N. Burdenko Neurosurgery Institute

P05.56 Treatment algorithm of patients with primary CNS germinoma: the experience of N.N. Burdenko Neurosurgery Institute

CNS germinomas are characterized by global demethylation, chromosomal instability and mutational activation of the Kit-, Ras/Raf/Erk- and Akt-pathways.

CNS germinomas represent a unique germ cell tumor entity characterized by undifferentiated tumor cells and a high response rate to current treatment protocols. Limited information is available on their underlying genomic, epigenetic and biological alterations. We performed a genome-wide analysis of genomic copy number alterations in 49 CNS germinomas by molecular inversion profiling. In addition, CpG dinucleotide methylation was studied by immunohistochemistry for methylated cytosine residues. Mutational analysis was performed by resequencing of candidate genes including KIT and RAS family members. Ras/Erk and Akt pathway activation was analyzed by immunostaining with antibodies against phospho-Erk, phosho-Akt, phospho-mTOR and phospho-S6. All germinomas coexpressed Oct4 and Kit but showed an extensive global DNA demethylation compared to other tumors and normal tissues. Molecular inversion profiling showed predominant genomic instability in all tumors with a high frequency of regional gains and losses including high level gene amplifications. Activating mutations of KIT exons 11, 13, and 17 as well as a case with genomic KIT amplification and activating mutations or amplifications of RAS gene family members including KRAS, NRAS and RRAS2 indicated mutational activation of crucial signaling pathways. Co-activation of Ras/Erk and Akt pathways was present in 83% of germinomas. These data suggest that CNS germinoma cells display a demethylated nuclear DNA similar to primordial germ cells in early development. This finding has a striking coincidence with extensive genomic instability. In addition, mutational activation of Kit-, Ras/Raf/Erk- and Akt- pathways indicate the biological importance of these pathways and their components as potential targets for therapy.

Preservation of KIT genotype in a novel pair of patient-derived orthotopic xenograft mouse models of metastatic pediatric CNS germinoma.

Metastatic intracranial germinoma is difficult to treat. Although the proto-oncogene KIT is recognized as one of the most frequent genetic abnormalities in CNS germinoma, the development of new target therapeutic agents for CNS germinoma is hampered by the lack of clinically-relevant animal models that replicate the mutated or over-expressed KIT. CNS germinoma tumor cells from five pediatric patients were directly implanted into the brains of Rag2/severe combined immune deficiency mice. Once established, the xenograft tumors were sub-transplanted in vivo in mouse brains. Characterization of xenograft tumors were performed through histologic and immunohistochemical staining, and KIT mutation analysed with quantitative pyro-sequencing. Expression of putative cancer stem cell markers (CD133, CD15, CD24, CD44, CD49f) was analyzed through flow cytometry. Two patient-derived orthotopic xenograft (PDOX) models (IC-6999GCT and IC-9302GCT) were established from metastatic germinoma and serially sub-transplanted five times in mouse brains. Similar to the original patient tumors, they both exhibited faint expression (+) of PLAP, no expression (-) of β-HCG and strong (+++) expression of KIT. KIT mutation (D816H), however, was only found in IC-9320GCT. This mutation was maintained during the five in vivo tumor passages with an increased mutant allele frequency compared to the patient tumor. Expression of putative cancer stem cell markers CD49f and CD15 was also detected in a small population of tumor cells in both models. This new pair of PDOX models replicated the key biological features of pediatric intracranial germinoma and should facilitate the biological and pre-clinical studies for metastatic intracranial germinomas.

GC-02 * CNS GERMINOMAS ARE CHARACTERIZED BY GLOBAL DEMETHYLATION, CHROMOSOMAL INSTABILITY AND MUTATIONAL ACTIVATION OF THE KIT-, RAS/RAF/ERK- AND AKT-PATHWAYS

CNS germinomas represent a unique germ cell tumor entity characterized by uniform undifferentiated tumor cells and a high response rate to current treatment protocols. However, only limited information is available on their underlying genomic, epigenetic and biological alterations. In this study we perfomed a genome-wide analysis of genomic copy number alteration and allelic disbalances in 37 cases of CNS germinomas by molecular inversion profiling. In addition, CpG dinucleotide methylation was studied by immunohistochemistry with a specific antibody against methylated cytosine residues. Mutational analysis was performed by resequencing of candidate genes including KIT and RAS family members using FFPE derived DNA. Ras/Erk and Akt pathway activation was analysed by immunostaining with specific antibodies against phospho-Erk and phospho-Akt. All germinomas coexpressed Oct4 and Kit but showed an extensive global demethylation of nuclear DNA compared to other germ cell tumors and normal tissues. Molecular inversion profiling showed predominant genomic instability in 32/37 tumors with a high frequency of regional gains and losses including high level amplifications. Activating mutations of KIT exons 11, 13, 17 as well as a case with genomic KIT amplification and activating mutations or amplifications of RAS gene family members including KRAS, NRAS, RRAS2 and RHOH as well as mutation of BRAF indicated mutational activation of crucial signalling pathways. Activation of both, Ras/Erk and Akt pathways was demonstrated by immunohistochemistry of phospho-Erk and phospho-Akt in germinomas. These data suggest that CNS germinoma cells display a demethylated nuclear DNA similar to primordial germ cells in early development. This finding is associated with extensive genomic instability in the majority of germinomas. In addition, mutational activation of KIT, Ras/Raf/Erk- and Akt- pathways is characteristic indicating the biological importance of these pathways and potential targets for therapy.

GE-13 * A NOVEL ASSOCIATION OF PRIMARY CNS GERMINOMA IN A PATIENT WITH NAIL PATELLA SYNDROME

Nail patella syndrome (NPS) is an autosomal dominant disorder with a prevalence of 1/50,000 characterized by developmental abnormalities of the nails, knees and elbows, as well as renal dysplasia and open angle glaucoma. NPS is caused by a mutation in the LMX1B gene, a transcription factor involved in ventral/dorsal patterning of the vertebrate limb. While malignancy is rare in patients with NPS, Ewing's sarcoma and colon cancer have been reported. Additionally, NPS has been described in a 5 generation family with neurofibromatosis type 1. We report a novel association of NPS with primary CNS germinoma. A 22-year-old male presented with a two-month history of diabetes insipidus (DI) and headaches. Physical examination revealed partial Parinaud's syndrome, dystrophic nails and surgical repair of left hypoplastic patella. Because the family history revealed numerous maternal family members with dystrophic nails and hypoplastic patellae, we subsequently made a formal clinical diagnosis of NPS. Contrast enhanced MRI of the brain revealed an enhancing cystic pineal mass and a Chiari I malformation; serum and CSF alpha-fetoprotein and beta-human chorionic gonadotropin were negative. Biopsy of the pineal mass was consistent with pure germinoma for which the patient received external beam radiation therapy via intensity modulated radiation therapy (IMRT) as follows: 1) 2520 cGy to the craniospinal axis; 2) 5040 cGy to the pineal region; 3) and 4620 cGy to the suprasellar region (for presumed tumor in the posterior pituitary given the history of DI). He remains in remission 9 years post-treatment. For the NPS, the patient declined referral to genetics due to insurance concerns but he and his family have been referred to appropriate services for screening of other abnormalities associated with the syndrome. This case report suggests that LMX1B may play a role in the development of CNS germinoma.

Intensive chemotherapy followed by reduced-dose radiotherapy for biopsy-proven CNS germinoma with elevated beta-human chorionic gonadotropin

In this study, 10 patients with biopsy-proven germinoma with a beta-human chorionic gonadotropin (β-HCG) level >50 mIU/ml received intensive chemotherapy followed by reduced-dose radiotherapy (RT) to reduce late effects from RT. CSF β-HCG levels were >200 mIU/ml in five patients. After endoscopic or stereotactic biopsy, four cycles of induction chemotherapy were administered prior to RT. A CEB regimen (carboplatin+etoposide+bleomycin) and a CyEB regimen (cyclophosphamide+etoposide+bleomycin) were alternated. No residual tumor remained after induction chemotherapy in six patients, only cystic lesions were present at the primary tumor site in three, and a small solid residual tumor was observed in the remaining patient; however, all these patients had normal β-HCG levels. If complete response was achieved before initiation of RT, 19.5Gy craniospinal RT (CSRT)+10.8Gy local RT was administered to the tumor bed. If residual lesion was suspected, the dose of RT was selected according to the presence/absence of tumor dissemination at diagnosis (19.5Gy CSRT+19.8Gy local RT for localized tumors and 24.0Gy CSRT+16.2Gy local RT for disseminated tumors). Eight patients, including four patients with a β-HCG level >200mIU/ml, received 19.5Gy CSRT. All patients remain disease free at a median follow-up of 58 (range 35-94) months from diagnosis. Our data suggest that pathologically pure germinoma with a significantly elevated β-HCG level might be cured with reduced-dose RT if intensive chemotherapy is provided.

Avoidance of swallowing saliva: A symptom related to aberrant basal ganglia functions?

We report two patients with avoidance of swallowing saliva despite intact swallowing functions. One, with mild, de novo Parkinson's disease, had a fear that his saliva was contaminated and would harm him. The other, with a history of CNS germinoma in remission for 3 years following chemotherapy, expectorated because his saliva was distasteful and disgusting. He had a lesion involving the left pallidum. Both appeared obsessed with the idea of saliva contamination and both expectorated compulsively, presenting obsessive–compulsive disorder (OCD) symptoms. OCD-like behavior may be induced in association with pathological conditions in which aberrant basal ganglia functions are present.