Radiomic- and dosiomic-based clustering development for radio-induced neurotoxicity in pediatric medulloblastoma

BACKGROUND

Texture analysis extracts many quantitative image features, offering a valuable, cost-effective, and non-invasive approach for individual medicine. Furthermore, multimodal machine learning could have a large impact for precision medicine, as texture biomarkers can underlie tissue microstructure. This study aims to investigate imaging-based biomarkers of radio-induced neurotoxicity in pediatric patients with metastatic medulloblastoma, using radiomic and dosiomic analysis.

METHODS

This single-center study retrospectively enrolled children diagnosed with metastatic medulloblastoma (MB) and treated with hyperfractionated craniospinal irradiation (CSI). Histological confirmation of medulloblastoma and baseline follow-up magnetic resonance imaging (MRI) were mandatory. Treatment involved helical tomotherapy (HT) delivering a dose of 39 Gray (Gy) to brain and spinal axis and a posterior fossa boost up to 60 Gy. Clinical outcomes, such as local and distant brain control and neurotoxicity, were recorded. Radiomic and dosiomic features were extracted from tumor regions on T1, T2, FLAIR (fluid-attenuated inversion recovery) MRI-maps, and radiotherapy dose distribution. Different machine learning feature selection and reduction approaches were performed for supervised and unsupervised clustering.

RESULTS

Forty-eight metastatic medulloblastoma patients (29 males and 19 females) with a mean age of 12 ± 6 years were enrolled. For each patient, 332 features were extracted. Greater level of abstraction of input data by combining selection of most performing features and dimensionality reduction returns the best performance. The resulting one-component radiomic signature yielded an accuracy of 0.73 with sensitivity, specificity, and precision of 0.83, 0.64, and 0.68, respectively.

CONCLUSIONS

Machine learning radiomic-dosiomic approach effectively stratified pediatric medulloblastoma patients who experienced radio-induced neurotoxicity. Strategy needs further validation in external dataset for its potential clinical use in ab initio management paradigms of medulloblastoma.

Vascular complications in craniopharyngioma-resected paediatric patients: a single-center experience

Background

Craniopharyngioma (CP), although slow growing and histologically benign, has high morbidity, mostly related to hypothalamus-pituitary dysfunction and electrolyte imbalance. Increased risk of vascular complications has been described. However, data are still poor, especially in the paediatric population. The aim of our study was to evaluate the occurrence, timing, and predisposing factors of deep venous thrombosis (DVT) and other vascular alterations in neurosurgical paediatric CP patients.

Materials and Methods

In a single-centre, retrospective study, we investigated 19 CP patients (11 males, 8 females, mean age 10.5 ± 4.3 years), who underwent neurosurgery between December 2016 and August 2022, referred to Meyer Children's Hospital IRCCS in Florence.

Results

Five patients (26.3%) presented vascular events, which all occurred in connection with sodium imbalances. Three DVT (two with associated pulmonary embolism, in one case leading to death) developed in the post-operative period, most frequently at 7-10 days. Elevated D-dimers, a reduced partial activated thrombin time and a prolonged C-reactive protein increase were highly related to thrombotic vascular events. One case of posterior cerebral artery pseudoaneurysm was described soon after neurosurgery, requiring vascular stenting. Superficial vein thrombophlebitis was a late complication in one patient with other predisposing factors.

Conclusion

CP patients undergoing neurosurgery are at risk of developing DVT and vascular alterations, thus careful follow-up is mandatory. In our study, we found that the phase of transition from central diabetes insipidus to a syndrome of inappropriate antidiuretic hormone secretion may be a period of significant risk for DVT occurrence. Careful vascular follow-up is mandatory in CP-operated patients.

Corrigendum: Bevacizumab-Irinotecan combination therapy in recurrent low-grade glioma, previously treated with chemo-radiotherapy: a case report

[This corrects the article DOI: 10.3389/fonc.2023.1244628.].

Bevacizumab-Irinotecan combination therapy in recurrent low-grade glioma, previously treated with chemo-radiotherapy: a case report

Low grade gliomas (LGGs) of pineal region are usually difficult to remove and they frequently relapse or progress after front line chemotherapy. Bevacizumab-Irinotecan (BEVIRI) combination has been successfully attempted in children with recurrent LGGs, in most cases not previously irradiated. The efficacy of bevacizumab has also been described in radiation necrosis. Considering the possible overlapping of radiation treatment effect and disease progression and difficulty in differentiating, we report on the use of BEVIRI in a case of a recurrent relapsing low-grade glioma of the pineal region, subjected to multiple neurosurgical interventions, also treated with a carboplatin-etoposide regimen and a radiation course, at present at one-year follow-up showing a stable response, with no adverse events.

Robot-assisted transcerebellar stereotactic approach to the posterior fossa in pediatric patients: a technical note

PURPOSE

During the last decade, there has been renewed interest in stereotactic approaches to diffuse intrinsic pontine gliomas (DIPGs) in children, due to the development of new concepts in molecular biology and management, and subsequent need for tissue sampling. Stereotactic frame-based and robot-assisted techniques are associated with reduced target error and have been incorporated into standard practice at our institution.

METHODS

Four children (age 2-7 years) underwent a robot-assisted frame-based transcerebellar approach using the Leksell G frame coupled with Renishaw's neuromate® stereotactic robot. The procedures included 3 biopsies (two brainstem tumors and one cerebellar hemispheric lesion) and 1 depth electrode implantation into a low-grade tumor remnant (ganglioglioma) of the middle cerebellar peduncle causing drug-resistant epilepsy in a young girl. Targeting was based on MRI, and in one case, 18F-FET-PET was coregistered to MRI to improve sampling accuracy. The frame was applied 180° rotated compared to standard orientation, and patients were positioned prone during surgery and stereotactic preoperative CT scan. Postoperative CT scan ruled out complications and was coregistered to preoperative MRI to check the target accuracy.

RESULTS

No complications occurred, and targeting was accurate in all cases. All tissue samplings provided proper histology; depth electrode EEG exploration was diagnostic and led subsequent resective surgery.

CONCLUSIONS

According to our experience, the transcerebellar frame-based robotic stereotactic approach to the cerebellum and the brainstem is feasible, safe, and effective even in young children.

Brief report: pediatric high-grade gliomas treated with vinorelbine and valproic acid added to temozolomide

Children and young adult with high grade gliomas (HGG) have dismal prognoses and treatment options remain limited. We present 19 patients diagnosed with anaplastic astrocytoma (AA) or glioblastoma (GBM) treated with concomitant and adjuvant 20-30 mg/m2/dose of vinorelbine and 30 mg/kg/day valproic acid (VA) in combination to consolidated TMZ and focal RT after maximal surgery. We evaluated the feasibility of treating children diagnosed with HGG. The median follow-up time was 51.4 months (range, 6.2-106.6 months). The 5-year OS was 57.9% (CI 95%, 33.2-76.3) and the 5-year PFS was 57.9% (CI 95%, 33.2-76.3). Eight patients (42.1%) have progressed so far, with a median time to progression of 9 months from diagnosis (range, 4.6-34.7 months). All of them died for disease progression. At time of analysis, 11 patients were still alive with no evidence of disease. It is notable that all events occurred within 35 months from the start of therapy. All 19 treated patients reported low-grade drug-related adverse events (AEs). The treatment was well tolerated in our limited cohort of patients without significant toxicity. Further studies of the efficacy and safety of combination of vinorelbine/VA to consolidated RT/TMZ therapy in children with HGG are underway in a clinical trial setting.

Unforeseen cytomegalovirus retinopathy following high dose thiotepa and proton irradiation in a pediatric patient with high-risk medulloblastoma: A case report

In immunocompetent individuals, cytomegalovirus (CMV) infection is usually mild but may cause severe complications such as retinitis, pneumonitis, and encephalitis in immunocompromised individuals. So far, cases of CMV retinitis in patients with medulloblastoma undergoing chemotherapy and radiotherapy, have not been reported. We herein report the case of a pediatric patient with high-risk medulloblastoma who experienced an unexpected CMV retinopathy and leukoencephalopathy following high dose thiotepa and proton irradiation. The patient underwent a four-course induction therapy (1st cycle: methotrexate and vinorelbine; 2nd cycle: etoposide and hematopoietic stem cells apheresis; 3rd cycle: cyclophosphamide and vinorelbine; 4th cycle: carboplatin and vinorelbine) and then a consolidation phase consisting in high dose thiotepa followed by autologous HSC transplant and proton cranio-spinal irradiation plus boost to the primary tumor site and pituitary site with concomitant vinorelbine. After two months of maintenance treatment with lomustine and vinorelbine, the patient showed complete blindness and leukoencephalopathy. A diagnosis of CMV retinopathy was made and oral valganciclovir was administered. CMV retinopathy was judged to be possibly related to the use of high dose thiotepa worsened by radiotherapy. This case report suggests that in pediatric patients undergoing immunosuppressive chemo-radiotherapy, CMV reactivation should be carefully monitored to prevent serious complications such as retinopathy and visual loss.

P17.13.A Verteporfin inhibits autophagy in glioblastoma cell lines

Background

Glioblastoma (GBM) is the most common primary brain tumor with a poor prognosis, characterized by a high cellular heterogeneity and invasiveness. Multi-drug resistance (MDR), the blood brain barrier (BEE) and DNA repair systems let the survival of tumor cells, making the treatment with chemo and radiotherapy not effective. Autophagy is a physiological mechanism that allows the recycling of damaged proteins and organelles, in order to protect the correct cell turnover. However, in GBM this process promotes survival and proliferation in stressful conditions such as after a chemo and / or radiotherapy treatment. The Hippo pathway is an extremely important molecular signaling because it is involved in various tumorigenesis processes, for instance the epithelium-mesenchymal transition (EMT), in the increase of stemness, mechanotransduction and chemoresistance.

Material and Methods

The modulation of autophagy was evaluated in GBM cell lines (U87MG, T98G and A172) exploiting a fluorescent detection that allowed the quantification of the autophagosomal activity present into the cell lines. The rate of autophagy was assessed after the cell lines pharmacological treatment with Hippo pathway inhibitors, Verteporfin 2uM (VP) for 24h, Latrunculin 0,5uM (LAT) for 3h and Cytochalasin 1uM (CIT) for 3h, with Doxorubicin 0,5uM (DOX) for 24h and with the drugs combination (DOX-VP, DOX-LAT and DOX-CIT). Moreover, the expression of the autophagy marker LC3II / I was evaluated in all three GBM cell lines by Western Blotting (WB) experiments. To perform this technique, the cells were treated with DOX and Hippo pathway inhibitors respecting the pharmacological treatment previously used. Then, the proteins were extracted, quantified and finally the WB was performed.

Results

The results obtained showed that the three GBM cell lines without any drugs were marked by high levels of autophagy, similar to the cells treated with Rapamycin, an autophagy inducer. Moreover, the autophagy rate was definitely reduced after treatment with VP and DOX-VP in all three cell lines, including the chemoresistant T98G. Conversely, the other two Hippo pathway inhibitors (LAT-CIT) and DOX did not significantly change the rate of autophagy. The expression of LC3II / I was particularly low after treatment with VP and DOX-VP in all three cell lines while the other two inhibitors did not significantly change its expression.

Conclusion

In conclusion, these data demonstrated that the three GBM cell lines (U87MG, T98G and A172) are characterized by high levels of autophagy and the inhibition of the Hippo pathway with VP and especially the combination DOX-VP reduced the activation of this protumoral molecular mechanism in GBM cell lines.

Optical Coherence Tomography Significance in Managing Early Onset of Optic Pathway Gliomas in Children Younger than 5 Years of Age—A Retrospective Study

We aimed to investigate the significance of optical coherence tomography (SD-OCT) in managing pediatric optic pathway gliomas (OPGs) in children younger than 5 years of age. A retrospective monocentric study was conducted. SD-OCT scans were obtained using the handheld iVue system to assess peripapillary retinal nerve fibre layer (pRNFL) thickness at three time points: baseline (OCT1), end of treatment (OCT2), and at last follow-up (OCT3). We compared the median value of pRNFL (and interquartile range—IQR) at different follow-up times and in different sub-groups (stable disease—SD, partial response—PR, and progression disease—PD). Thirteen children younger than 5 years of age were included. The Median follow-up time was 3.9 years (IQR 1.2). Six patients showed a pRNFL change of more than 10% during follow-up. Seven patients showed PD during follow-up. Median pRNFL at baseline was 81.5 µm (IQR 31.5); median pRNFL at the end of treatment was 73 µm (IQR 33); median pRNFL at last follow-up was 72 µm (IQR 38.5). The mean pRNFL at baseline was significantly lower than the mean normative values. Only subjects with PD showed pRNFL change close to statistical significance. This study confirms the role of SD-OCT in managing OPGs for therapeutic decisions and strategy planning of visual rehabilitation.

Diencephalic syndrome in childhood, a challenging cause of failure to thrive: miniseries and literature review

The aim of our study was to better define the clinical pattern of diencephalic syndrome, a rare but potentially lethal cause of failure to thrive in infancy. Poor weight gain or weight loss, the characteristic presenting feature, often firstly attributed to gastrointestinal or endocrinological or genetic diseases, is secondary to a malfunctioning hypothalamus, caused by a diencephalic tumor. Due to its unexpected clinical onset, diagnostic delay and misdiagnosis are common. We described a case series of 3 children with diencephalic syndrome admitted at our Hospital, over a 5-year period. Furthermore, a narrative review on all pediatric cases published in the last seventy years was performed. Clinical pattern, timing to diagnosis, neuroimaging, management, and outcome were analyzed. Our three cases are singularly described in all clinical and diagnostic findings. Overall, 100 children were selected; all these cases as well as our children presented with failure to thrive: 96% had body mass index or weight-length/height ratio lower than 5^th percentile. Vomiting and hyperactivity are reported in 35 and 26% of cases, respectively. The neurological features, mainly nystagmus reported in 43%, may occur late in the disease course. In conclusion, the diagnostic delay is the hallmark of diencephalic syndrome, confirming the lack of knowledge by clinicians. The poor weight gain/loss despite adequate length growth and food intake, especially in children with hyperactivity and good psychomotor development, should alert pediatricians towards this condition, before neurological signs/symptoms occurrence.

Pleomorphic Xanthoastrocytoma: a single institution retrospective analysis and a review of the literature

Background

 Pleomorphic xanthoastrocytoma (PXA) is a rare low-grade brain tumor. To date, limited studies have analyzed factors affecting survival outcomes and defined the therapeutic strategy. The aim of this retrospective analysis was to investigate the clinicopathologic characteristics of PXA and identify factors associated with outcomes.

Methods

 We retrospectively analyzed a cohort of 16 adult and children patients with PXA who underwent primary resection from 1997 to 2019, referred to our Radiation Oncology Unit and to Meyer’s Paediatric Hospital. We also reviewed the relevant literature.

Results

 All patients underwent primary surgical resection; 10 patients received adjuvant radiation treatment course, ranging from DTF 54 to 64 Gy; 8 of them received, in addition, concurrent adjuvant chemotherapy; 6 patients underwent only radiological follow-up. After a median follow up was 60 months: median OS was 34.9 months (95% CI 30–218), 1-year OS 87%, 5-years OS 50%, 10-years OS 50%; median PFS 24.4 months (95% CI 13–156), 1-year PFS 80%, 5-years PFS 33%, 10-years PFS 33%. A chi-square test showed a significant association between OS and recurrent disease (p = 0.002) and with chemotherapy adjuvant treatment (p = 0.049). A borderline statistical significant association was instead recognized with BRAF mutation (p = 0.058).

Conclusions

Despite our analysis did not reveal a strong prognostic or predictive factor able to address pleomorphic xanthoastrocytoma management; however, in selected patients could be considered the addition of adjuvant radiation chemotherapy treatment after adequate neurosurgical primary resection. Furthermore, recurrent disease evidenced a detrimental impact on survival.

QOL-25. Neurocognitive assessment of pediatric medulloblastoma treated by MBMET_MEYER trial. Censullo M.L1, Bertoluzzo G2, Fonte C1, Pavone R1, Guidi M1, Enrico G1, Gori C.G1, Martin R2, Teodori C2, Sardi I1 1Neuro-Oncology Unit, Department of Pediatric Oncology, Meyer Children’s University Hospital, Florence, Italy2Psychology Unit, Meyer Children’s University Hospital, Florence, Italy

The MBMET_MEYER is an interventistic monocentric trial of Meyer Children’s Hospital. The goal of this protocol is to reduce toxicity by use of protontherapy and reducing chemo-induced neurotoxicity by limited use of high dose chemotherapy. To date, a neurocognitive assessment is the standard in medulloblastomas but it is very difficult an assessment at baseline for clinical problems such as age, intracranial hypertension and immediate intervention. 10 neurocognitive assessments were reviewed in patients with medulloblastoma treated by MBMET_MEYER protocol: 3 anaplastic medulloblastoma M0 and 7 classic (2 M0, 1 M1, 1 M2, 3 M3). The median age was 10 years (range 5-18). All the patients were treated with surgery (gross total removal), 2 received chemotherapy and conventional radiotherapy, 8 chemotherapy and protontherapy and only 1 received autologos-hemotopoietic stem cell transplant for progression disease after induction chemotherapy. As for protocol, the neurocognitive assessment was defined by Weschler Intelligence Scales, fonemic and semantic fluency, immediate and deferred memory, tests for working memory, attention and visuo-spatial tests at baseline, after treatment and at the end of follow-up. For 3 patients it was not possible a baseline assessment for bad clinic conditions, 8 are still in treatment. From interviews and assessments emerged that 80% of patients had neurocognitive deficits: at baseline 5 had speed elaboration difficulties, 1 of these also presented verbal deficit, 1 showed problems in recalling verbal material and 1 in working memory; after two years from chemotherapy and radiotherapy 2 presented speed processig and working memory deficit. In conclusion, an assessment at baseline is very difficult for post-surgical problems but necessary to perform as soon. In this way, it is possible to evaluate the impact of the treatment on neurocognitive impairment. Further investigations are necessary to well understand the appropriate schedule of neurocognitive assessment of pediatric medulloblastoma.

GCT-01. Pediatric intracranial germ cell tumors and primary polyuria-polydipsia syndrome: a 13-year single institutional experience

Intracranial germ cell tumors (IGCTs) represent about 4% of all childhood brain tumors. They are common in both the pineal and pituitary regions and sometimes they can be bifocal. Suprasellar and bifocal IGCTs usually present stereotypical symptoms, including primary polyuria-polydipsia syndrome (PPS). Consolidated IGCTs’ therapy is based on the International Society of Pediatric Oncologic (SIOP) CNS GCT II protocol consisting of primary pre-radiation chemotherapy combining etoposide, carboplatin and/or cisplatin and ifosfamide. PPS management in these patients requires monitoring of electrolytes and fluids during chemotherapy, especially for cisplatin and/or ifosfamide-based cycles, for which hyperhydratation is required. We report the results of our single-center cohort of patients with IGCTs treated between 2008 and 2021, focusing on the clinical presentation, treatment and long-term follow-up. Thirty-one patients were analyzed (median age=13 years, 87% male). Twelve children (39%) presented a PPS and needed desmopressin treatment, maintained at long-term follow-up data update in all. Over these PPS patients, 6 had bifocal germinomas, 4 suprasellar germinomas, 1 metastatic germinoma and 1 non-germinomatous IGCT. Eleven PPS children (92%) received cisplatin and/or ifosfamide-based chemotherapy: all of them had optimal biochemical urine and blood investigations before, during and after chemotherapy. None of them presented serious complications during treatment. After a median follow-up of 5 years, two patients (6.5%) died (1 IGCT-related, 1 non-cancer related) and one had a second malignancy (parotid gland mucoepidermoid carcinoma, 6 years after IGCT diagnosis). Childhood IGCTs have an excellent prognosis, but present a significant risk of long-lasting severe endocrine sequelae which may be worsened by the primary oncological strategy, requiring careful management of complications related to fluid and electrolytes disturbances. In order to avoid post-treatment pituitary insufficiency, guidelines for diabetes insipidus management when cisplatin and/or ifosfamide-based protocols are used should be established and all patients should receive meticulous endocrine follow-up.

Toxicity and Clinical Results after Proton Therapy for Pediatric Medulloblastoma: A Multi-Centric Retrospective Study

Medulloblastoma is the most common malignant brain tumor in children. Even if current treatment dramatically improves the prognosis, survivors often develop long-term treatment-related sequelae. The current radiotherapy standard for medulloblastoma is craniospinal irradiation with a boost to the primary tumor site and to any metastatic sites. Proton therapy (PT) has similar efficacy compared to traditional photon-based radiotherapy but might achieve lower toxicity rates. We report on our multi-centric experience with 43 children with medulloblastoma (median age at diagnosis 8.7 years, IQR 6.6, M/F 23/20; 26 high-risk, 14 standard-risk, 3 ex-infant), who received active scanning PT between 2015 and 2021, with a focus on PT-related acute-subacute toxicity, as well as some preliminary data on late toxicity. Most acute toxicities were mild and manageable with supportive therapy. Hematological toxicity was limited, even among HR patients who underwent hematopoietic stem-cell transplantation before PT. Preliminary data on late sequelae were also encouraging, although a longer follow-up is needed.

MDACT: A New Principle of Adjunctive Cancer Treatment Using Combinations of Multiple Repurposed Drugs, with an Example Regimen

In part one of this two-part paper, we present eight principles that we believe must be considered for more effective treatment of the currently incurable cancers. These are addressed by multidrug adjunctive cancer treatment (MDACT), which uses multiple repurposed non-oncology drugs, not primarily to kill malignant cells, but rather to reduce the malignant cells' growth drives. Previous multidrug regimens have used MDACT principles, e.g., the CUSP9v3 glioblastoma treatment. MDACT is an amalgam of (1) the principle that to be effective in stopping a chain of events leading to an undesired outcome, one must break more than one link; (2) the principle of Palmer et al. of achieving fractional cancer cell killing via multiple drugs with independent mechanisms of action; (3) the principle of shaping versus decisive operations, both being required for successful cancer treatment; (4) an idea adapted from Chow et al., of using multiple cytotoxic medicines at low doses; (5) the idea behind CUSP9v3, using many non-oncology CNS-penetrant drugs from general medical practice, repurposed to block tumor survival paths; (6) the concept from chess that every move creates weaknesses and strengths; (7) the principle of mass-by adding force to a given effort, the chances of achieving the goal increase; and (8) the principle of blocking parallel signaling pathways. Part two gives an example MDACT regimen, gMDACT, which uses six repurposed drugs-celecoxib, dapsone, disulfiram, itraconazole, pyrimethamine, and telmisartan-to interfere with growth-driving elements common to cholangiocarcinoma, colon adenocarcinoma, glioblastoma, and non-small-cell lung cancer. gMDACT is another example of-not a replacement for-previous multidrug regimens already in clinical use, such as CUSP9v3. MDACT regimens are designed as adjuvants to be used with cytotoxic drugs.

Pediatric High Grade Glioma Classification Criteria and Molecular Features of a Case Series

Pediatric high-grade gliomas (pHGGs) encompass a heterogeneous group of tumors. Three main molecular types (H3.3 mutant, IDH mutant, and H3.3/IDH wild-type) and a number of subtypes have been identified. We provide an overview of pHGGs and present a mono-institutional series. We studied eleven non-related pHGG samples through a combined approach of routine diagnostic tools and a gene panel. TP53 and H3F3A were the most mutated genes (six patients each, 54%). The third most mutated gene was EGFR (three patients, 27%), followed by PDGFRA and PTEN (two patients each, 18%). Variants in the EZHIP, MSH2, IDH1, IDH2, TERT, HRAS, NF1, BRAF, ATRX, and PIK3CA genes were relatively infrequent (one patient each, 9%). In one case, gene panel analysis documented the presence of a pathogenic IDH2 variant (c.419G>A, p.Arg140Gln) never described in gliomas. More than one-third of patients carry a variant in a gene associated with tumor-predisposing syndromes. The absence of constitutional DNA did not allow us to identify their constitutional origin.

Expert Opinion on the Management of Growth Hormone Deficiency in Brain Tumor Survivors: Results From an Italian Survey

BACKGROUND

Growth hormone deficiency (GHD) is the first and most common endocrine complication in pediatric brain tumor survivors (BTS). GHD can occur due to the presence of the tumor itself, surgery, or cranial radiotherapy (CRT).

AIMS

This study aimed to evaluate management and adherence to current guidelines of the Italian centers engaged in the diagnosis and follow-up of GHD patients with BTS.

METHODS

A multidisciplinary scientific board of pediatric endocrinologists, oncologists and radiologists with neuroimaging expertise discussed and reviewed the main issues relating to the management of GHD in pediatric BTS and developed a survey. The survey included questions relating to organizational aspects, risk factors, diagnosis, definition of stable disease, and treatment. The online survey was sent to an expanded panel of specialists dedicated to the care of pediatric BTS, distributed among the three specialty areas and throughout the country (23 Italian cities and 37 Centers).

RESULTS

The online questionnaire was completed by 86.5% (32 out of 37) of the Centers involved. Most had experience in treating these patients, reporting that they follow more than 50 BTS patients per year. Responses were analyzed descriptively and aggregated by physician specialty. Overall, the results of the survey showed some important controversies in real life adherence to the current guidelines, with discrepancies between endocrinologists and oncologists in the definition of risk factors, diagnostic work-up, decision-making processes and safety. Furthermore, there was no agreement on the neuroimaging definition of stable oncological disease and how to manage growth hormone therapy in patients with residual tumor and GHD.

CONCLUSIONS

The results of the first Italian national survey on the management of GHD in BTS highlighted the difference in management on some important issues. The time to start and stop rhGH treatment represent areas of major uncertainty. The definition of stable disease remains critical and represents a gap in knowledge that must be addressed within the international guidelines in order to increase height and to improve metabolic and quality of life outcomes in cancer survivors with GHD.

Hippo Pathway in Regulating Drug Resistance of Glioblastoma

Glioblastoma (GBM) represents the most common and malignant tumor of the Central Nervous System (CNS), affecting both children and adults. GBM is one of the deadliest tumor types and it shows a strong multidrug resistance (MDR) and an immunosuppressive microenvironment which remain a great challenge to therapy. Due to the high recurrence of GBM after treatment, the understanding of the chemoresistance phenomenon and how to stimulate the antitumor immune response in this pathology is crucial. The deregulation of the Hippo pathway is involved in tumor genesis, chemoresistance and immunosuppressive nature of GBM. This pathway is an evolutionarily conserved signaling pathway with a kinase cascade core, which controls the translocation of YAP (Yes-Associated Protein)/TAZ (Transcriptional Co-activator with PDZ-binding Motif) into the nucleus, leading to regulation of organ size and growth. With this review, we want to highlight how chemoresistance and tumor immunosuppression work in GBM and how the Hippo pathway has a key role in them. We linger on the role of the Hippo pathway evaluating the effect of its de-regulation among different human cancers. Moreover, we consider how different pathways are cross-linked with the Hippo signaling in GBM genesis and the hypothetical mechanisms responsible for the Hippo pathway activation in GBM. Furthermore, we describe various drugs targeting the Hippo pathway. In conclusion, all the evidence described largely support a strong involvement of the Hippo pathway in gliomas progression, in the activation of chemoresistance mechanisms and in the development of an immunosuppressive microenvironment. Therefore, this pathway is a promising target for the treatment of high grade gliomas and in particular of GBM.

Treatment and outcome of intracranial ependymoma after first relapse in AIEOP 2 nd protocol

BACKGROUND

More than 40% of patients with intracranial ependymoma need a salvage treatment within 5 years after diagnosis, and no standard treatment is available as yet. We report the outcome after first relapse of 64 patients treated within the 2 nd AIEOP protocol.

METHODS

We considered relapse sites and treatments ,i.e. various combinations of complete/incomplete surgery, if followed by standard or hypo-fractionated radiation(RT) ± chemotherapy(CT). Molecular analyses were available for 38/64 samples obtained at first diagnosis. Of the 64 cases, 55 were suitable for subsequent analyses.

RESULTS

The median follow-up was 147 months after diagnosis, 84 after first relapse, 5-year EFS/OS were 26.2%/30.8% (median EFS/OS 13/32 months) after relapse. For patients with a local relapse(LR), the 5-year cumulative incidence of second LRs was 51.6%, with a 5-year event-specific probability of being LR-free of 40.0%. Tumor site/grade, need for shunting, age above/below 3 years, molecular subgroup at diagnosis, had no influence on outcomes. Due to variation in the RT dose/fractionation used and the subgroup sizes it was not possible to assess the impact of the different RT modalities. Multivariable analyses identified completion of surgery, absence of symptoms at relapse, and female sex as prognostically favorable. Tumors with a 1q gain carried a higher cumulative incidence of dissemination after first relapse.

CONCLUSIONS

Survival after recurrence was significantly influenced by symptoms and completeness of surgery. Only a homogeneous protocol with well posed, randomized questions could clarify the numerous issues, orient salvage treatment and ameliorate prognosis for this group of patients.

P06.07 Germline mutation of SMARCE1 gene in a family with spinal meningiomas

BACKGROUND

Meningioma is the most common benign primary intracranial tumor, arising from arachnoid cells of the meninges, but in 20% of cases displays aggressive behavior. Meningiomas are mainly sporadic and the familial forms are very rare. Meningioma account for a small subset (1–4%) of all pediatric brain tumors and may be associated with hereditary tumor predisposition syndrome caused by germline mutations of NF2, SMARCB1, SUFU, and SMARCE1 genes.

MATERIAL AND METHODS

We present a case of a 16-year-old girl with spinal clear cell meningiomas (CCMs) WHO II with a second spinal lesion identified during the follow-up. Considering the multiple lesions, we performed Whole Exome Sequencing (WES) on DNA from peripheral blood to search for an underlying CCMs tumor predisposition syndrome (#607174).

RESULTS

We identified a heterozygous frameshift variant c.439delA (p.Ser147fs) in SMARCE1, chromatin remodelling factor that acts as a tumor suppressor gene. Meningioma analysis by Sanger sequencing showed a loss of heterozygosity (LOH) of the wild-type allele. We identified the c.439delA in the constitutional DNA of the father and the sister but not in the mother. At the moment, the father is asymptomatic and the 14 years old sister showed two spinal lesions (meningiomas likely) at the first MRI.

CONCLUSION

We report a family study of hereditary tumor predisposition syndrome to CCMs with SMARCE1 mutation in which are present two asymptomatic carriers with different ages and gender. The asymptomatic carriers will undergo neurological examination and MRI of the brain and spine, according to a screening protocol. The incomplete penetrance phenomenon is known in SMARCE1-related families with CCMs and it is probably due to the interaction of SMARCE1 with yet unidentified genes.

P04.20 The role of YAP in Glioblastoma cell lines

BACKGROUND

Glioblastoma (GBM) is a primary human malignant brain tumor, the most common in adults. Several studies have highlighted the Hippo-pathway as a cancer signalling network. The Hippo pathway is an evolutionarily conserved signal cascade, which is involved in the control of organ growth. Dysregulations among this pathway have been found in lung, ovarian, liver and colorectal cancer. The key downstream effector of the Hippo-pathway is the Yes-associated protein (YAP); in the nucleus, its function as transcription co-activator is to interact with transcription factors, resulting in the expression of target genes involved in pro-proliferating and anti-apoptotic programs.

MATERIAL AND METHODS

Using western blotting analysis, we determined the nuclear expression of YAP on three GBM cell lines (U87MG, T98G and A172). To investigate which inhibitors against the Hippo-pathway were the most efficient, we performed a cytotoxic assay: we treated all the three cell lines with different inhibitors such as Verteporfin (VP), Cytochalasin D (CIT), Latrunculin A (LAT), Dobutamine (DOB) and Y27632. Afterwards, we performed a treatment using Doxorubicin (DOX) combined with the inhibitors, evaluating its cytotoxic effect on our cell lines, through cell viability experiments. More western blotting experiments were performed to investigate the oncogenic role of YAP at nucleus level. Furthermore, preliminary experiments have been conducted in order to investigate the apoptosis, senescence and autophagy modulation due to the Hippo-pathway.

RESULTS

We showed our cell lines express nuclear YAP. We assessed the efficiency of the main inhibitors against Hippo-pathway, proving that VP, LAT A and CIT show a strong cytostatic effect, linked to time increase; plus we saw a cytotoxic effect on T98G. The association of DOX with selected inhibitors is able to reduce cell viability and nuclear YAP expression rate in all three GBM lines. Finally, preliminary experiments were set up to assess how and if the mechanisms of apoptosis, autophagy and senescence were affected by the Hippo-pathway. The combination of DOX with inhibitors promotes resistance to apoptosis.

CONCLUSION

Our results show that nuclear YAP is present in all tumor lines, thus confirming that this molecular pathway is functioning in GBM lines. Nuclear YAP is more highly expressed after DOX administration. Moreover, the combined treatment (DOX with Hippo-pathway inhibitors) reduces both cell proliferation and viability, and increases the rate of apoptosis. Preliminary experiments on senescence and autophagy were used to determine the best Hippo-pathway inhibitor. These data demonstrate that the Hippo-pathway plays a crucial role in GBM proliferation and resistance to apoptosis. Inhibiting this pathway and in particular the transcription factor YAP, in association with DOX, might be an excellent therapeutic target.

Dysembryoplastic neuroepithelial tumors: A single-institutional series with special reference to glutamine synthetase expression

Dysembryoplastic neuroepithelial tumors (DNT) is a benign (World Health Organisation, WHO, grade I) glioneuronal tumor and it represent one of the most frequent neoplasm in patient affected by seizures. The epileptic neuronal activity can be determined by abnormal synchronization, excessive glutamate excitation and\or inadequate GABA inhibition. Increasing evidence suggests that the astrocytes might be involved in this process even if neurons play a relevant role. In particular astrocytes promote the clearance of glutamate, a potent excitatory neurotransmitter of the central nervous system. Indeed, elevated concentrations of extracellular glutamate may determine iper-excitability and seizures as well as other neurological disorders. So, astrocytes, converting glutamate into glutamine via the enzyme glutamine synthetase (GS), could play a protective anti-seizures role. In the present study, we analyzed the immunohistochemical expression of GS in 20 DNTs specimens documenting a constant immunoistochemical expression of GS in astrocytes of the lesional tissue and of the cerebral cortex.

Primary Intracerebral Alveolar Soft Part Sarcoma: Report of a Case and Review of the Literature

Alveolar soft part sarcomas (ASPSs) are rare malignant tumors representing ∼1% of all soft tissue sarcomas. Most ASPS occurring in the central nervous system are metastases. In contrast, primary intracranial ASPSs are extremely rare and only 8 cases have been previously reported in English literature. Here, we report a case of primary alveolar soft part sarcoma in a 16-year-old female patient with no evidence of primary extracranial tumors. Histologically this case fulfilled the criteria of ASPS, and a molecular confirmation has been archived. To date, only 9 primary intracranial ASPS cases, including ours, have been reported in the literature. This report highlights the clinical and pathological characteristics, differential diagnosis, and molecular analysis of primary ASPS of the central nervous system.

Second series by the Italian Association of Pediatric Hematology and Oncology of children and adolescents with intracranial ependymoma: an integrated molecular and clinical characterization with a long-term follow-up

BACKGROUND

A prospective 2002-2014 study stratified 160 patients by resection extent and histological grade, reporting results in 2016. We re-analyzed the series after a median of 119 months, adding retrospectively patients' molecular features.

METHODS

Follow-up of all patients was updated. DNA copy number analysis and gene-fusion detection could be completed for 94/160 patients, methylation classification for 68.

RESULTS

Progression-free survival (PFS) and overall survival (OS) at 5/10 years were 66/58%, and 80/73%. Ten patients had late relapses (range 66-126 mo), surviving after relapse no longer than those relapsing earlier (0-5 y). On multivariable analysis a better PFS was associated with grade II tumor and complete surgery at diagnosis and/or at radiotherapy; female sex and complete resection showed a positive association with OS. Posterior fossa (PF) tumors scoring ≥0.80 on DNA methylation analysis were classified as PFA (n = 41) and PFB (n = 9). PFB patients had better PFS and OS. Eighteen/32 supratentorial tumors were classified as RELA, and 3 as other molecular entities (anaplastic PXA, LGG MYB, HGNET). RELA had no prognostic impact. Patients with 1q gain or cyclin-dependent kinase inhibitor 2A (CDKN2A) loss had worse outcomes, included significantly more patients >3 years old (P = 0.050) and cases of dissemination at relapse (P = 0.007).

CONCLUSIONS

Previously described prognostic factors were confirmed at 10-year follow-up. Late relapses occurred in 6.2% of patients. Specific molecular features may affect outcome: PFB patients had a very good prognosis; 1q gain and CDKN2A loss were associated with dissemination. To draw reliable conclusions, modern ependymoma trials need to combine diagnostics with molecular risk stratification and long-term follow-up.

Proton therapy: A therapeutic opportunity for aggressive pediatric meningioma

Meningiomas are an extremely rare histology among pediatric brain tumors, and there is a shortage of literature on their management. Proton therapy is currently used safely and effectively for many types of both pediatric and adult cancer, and its main advantage is the sparing of healthy tissues from radiation, which could translate in the reduction of late side effects. We review the literature on radiotherapy and proton therapy for pediatric meningiomas and report clinical outcomes for two aggressive pediatric meningiomas we treated with protons. Proton therapy might be a safe and effective therapeutic option for this rare subgroup of tumors.

Genetic signature and treatment of pediatric high-grade glioma

Pediatric high-grade glioma (HGG) is a type of malignancy that carries a poor prognosis. The genetic analysis of HGGs has previously identified useful mutations, the targeting of which has improved prognosis. Thus, further research into the more common mutations, such as H3 histone variants (HIST1H3B and H3F3A) and BRAF V600E, may be useful in identifying tumors with different prognoses, as the mutations are considered to drive two distinct oncogenic programs. The present study performed a retrospective analysis of pediatric HGGs. In total, 42 cases of HGG, including 32 cases (76.1%) of anaplastic astrocytoma and 10 cases (23.8%) of glioblastoma multiforme (GBM), were assessed. The median age of the patients was 7 years (range, 0-32 years). Mutations on histone H3, in particular the K27M and G34R mutations in the distinct variants HIST1H3B and H3F3A, in addition to the presence of the BRAF V600E mutation, were analyzed in 24 patients. The H3F3A K27M mutation was identified in 7 patients (29.1%), while the HIST1H3B K27M mutation was only observed in 1 patient with GBM. In addition, 5 patients harbored a BRAF V600E mutation (21%), while the H3F3A G34R mutation was not recorded in any of the patients. The overall survival of the wild-type patients at 20 months was 68% [confidence interval (CI): 38-85%] compared with 28% (CI: 0.4-60%) in patients with the H3F3A K27M mutation. These results suggested that patients with the H3F3A K27M mutation had a worse prognosis compared with wild-type patients (P=0.0045). Moreover, 3/5 patients with the BRAF V600E mutation had HGGs that were derived from a previous low-grade glioma (LGG; P=0.001). In conclusion, these results suggested that histone H3 mutations may help predict the outcome in patients with HGG. In addition, the BRAF V600E mutation was found to be associated with an increased risk of anaplastic progression. The novel data of the present study may help better define the clinical and radiological characteristics of glioma.

Optical coherence tomography significance in managing complex neurofibromatosis 2-related papilledema: Report of a case

This case describes the strong utility of optical coherence tomography in multidisciplinary management of a complex case of type 2 neurofibromatosis.

Case Report: A Case of Glioblastoma in a Patient With Haberland Syndrome

Haberland syndrome or encephalocraniocutaneous lipomatosis is a rare ectomesodermal dysgenesis defined by the triad including ocular, skin, and central nervous system involvement, which is commonly unilateral. This disorder is attributed to a post-zygotic mutation responsible for a neural tube and neural crest dysgenesis. We report the case of a 15-year-old female with Haberland syndrome with pharmacoresistant epilepsy who developed a World Health Organization-grade IV glioblastoma. This is the first case of pediatric glioblastoma associated with Haberland syndrome. The previously reported pediatric cases included benign brain tumors. To our knowledge, this is the fifth case of brain tumor associated with encephalocraniocutaneous lipomatosis and the second case of glioblastoma associated with this syndrome. The hypothesis that Haberland syndrome is associated with an increased risk of tumor development is intriguing, although the rarity of the condition is nowadays preventing us from drawing definitive conclusions about this potential link between the two entities. Further studies are needed to establish the real relationship between encephalocraniocutaneous lipomatosis and the risk of brain tumors.

EPEN-03. LONG-TERM FOLLOW-UP OF AIEOP 2ND SERIES OF CHILDREN AND ADOLESCENT WITH PRIMARY INTRACRANIAL (ST:SUPRATENTORIAL; PF: POSTERIOR FOSSA) EPENDYMOMA AND METHYLATION GROUPS RE-ANALYSES

BACKGROUND

This 2002–2014 Italian prospective study stratified 160 patients by surgical resection (complete=NED/incomplete=ED) and centrally-reviewed grade. Grade2/NED patients received focal radiotherapy (RT) up to 59.4Gy, Grade3/NED received 4 courses of VEC(vincristine,etoposide,cyclophosphamide) after RT.ED patients received 1–4 VEC courses, second-look surgery, 59.4 Gy+8Gy boost on measurable residue.

METHODS

We re-analyzed data at 115 months follow-up including methylation profile on available samples.

RESULTS

Global PFS/OS at 5/10 years were 66/59% and 80/74%, respectively. Of the 64 relapsers at median 20 months, 53 died at median 37/18 months after diagnosis/relapse, respectively.10/64 relapsed after 5 years (66–126 months); 4 died, relapse was local in 8/10, metastatic 1, combined 1;5/10 patients were below age 3, 5 females, 8 PF tumors. Their survival post-relapse was not longer than earlier relapsers’. At univariable analysis, age over 3 years, female sex, complete surgery, grade 2, no shunt confirmed better PFS/OS. 66/95 analyzed tumors received a score >0.80 through the DNA methylation-based central nervous system tumor classifier: 41/8 as PFA/PFB, respectively,14/17 ST as RELA-positive (3 scored for other molecular entities i.e. anaplastic PXA, LGG MYB, HGNET). Prognostic factors were equally distributed among PFA/PFB groups,1 only group B patient relapsed locally at 96 months.

CONCLUSIONS

Already published prognostic factors remained at long-term follow-up;6.2% patients had late relapses. OS after relapse was not better in late relapsers. Group B confirmed better prognosis but all patients had received «at least» adjuvant RT. Modern ependymoma trials need long follow-up to draw firm conclusions.

An alternative procedure to leukapheresis for peripheral hematopoietic progenitor cell collection in very-low-weight children: A single pediatric center experience

BACKGROUND

PBSC collection using a blood cell separator in very low weight patients can be frequently complicated by severe adverse effects and technical difficulties.

MATERIAL AND METHODS

From March 2013 to January 2017, 14 PBSC collections were performed in 12 children weighing less than 10 kg, affected by different solid tumours. PBSC collection was performed with a "homemade" aseptically assembled circuit. The circuit is composed by a 150 mL collection bag connected with a 4 stopcock ramp, perfused with ACD. This circuit allows collection of a specific total blood amount from CVC, depending on CD34⁺ /kg target.

RESULTS

Mean CD34⁺ cell performance per collection was 9.3 × 10⁶ /kg. Tolerance to the procedure was very good as none of the patients experienced complications, with the exception of a patient who showed mild cyanosis and pallor after collection. Moreover, no bleeding or thrombotic complications have been observed. To date, 16 PBSC reinfusions have been performed in 7 children with a mean CD34⁺ cells viability of 98.1% ± 2.7 and mean WBC viability of 57% ± 10. Cell recovery after thawing was 87% ± 10.8. A rapid graft intake for both neutrophils and platelets, between day 7 and 20 after reinfusion was observed.

DISCUSSION

The procedure of total blood collection without the use of a cell separator is feasible and allows a good PBSC collection without significant side effects in very low-weight children. Moreover, this method could represent a valid and safe alternative to leukapheresis in patients where classic procedure could be difficult to apply.

Neurosurgical treatment of subependymal giant cell astrocytomas in tuberous sclerosis complex: a series of 44 surgical procedures in 31 patients

BACKGROUND

Subependymal giant cell astrocytomas (SEGA) are benign tumors characteristic of tuberous sclerosis complex (TSC) that may cause hydrocephalus. Various treatments are nowadays available as mTOR inhibitors or surgery. Surgery is still a valid option especially for symptomatic and larger tumors.

METHODS

From January 1994 to December 2015, 31 TSC patients harboring SEGA underwent surgery at the Department of Neurosurgery of the Meyer Pediatric Hospital, Florence. Indications for surgery were tumor size and location, growth and cystization/hemorrhage, and hydrocephalus. Clinical data, preoperative and postoperative MRI, recurrence rate, further surgical procedures, and related complications were analyzed.

RESULTS

A total of 44 surgeries were performed in 31 TSC patients affected by SEGA, achieving gross total removal (GTR) and subtotal removal (STR), respectively, in 36 and 8 patients. Recurrences occurred in 11 patients; 9 of them underwent further surgical procedures and 2 were treated with mTOR pathway inhibitors. Surgical morbidity and mortality were, respectively, 22.7% and 2.3%. After a mean follow-up of 4.9 years, 90% of patients were tumor-free with good neurological status in 93.3%; twelve (40%) had a ventriculo-peritoneal shunt (VPS) for hydrocephalus.

CONCLUSIONS

The present series confirms that the surgical approach, combined with mTOR inhibitors, is still a valid option for the treatment of SEGAs.

Use of High-Dose Chemotherapy in Front-Line Therapy of Infants Aged Less Than 12 Months Treated for Aggressive Brain Tumors

Introduction: Malignant brain tumors in infants less than 12 months of age are extremely rare, and they have poor prognosis. We evaluated genetic characteristics and response rates of infants with congenital brain tumors subjected to high-dose chemotherapy and autologous stem cell transplant after gross total tumor resection. Materials and Methods: In total, 10 infants, aged less than 12 months, were enrolled in this study. The median age was 56 days (range: 1-279 days). Pathological examination demonstrated the following: four anaplastic astrocytomas, two glioblastomas, two central nervous system (CNS) embryonal tumors, not otherwise specified (NOS), and two atypical teratoid/rhabdoid tumors. Results: All patients were exposed to induction chemotherapy regimen, two high-dose chemotherapy courses, and autologous stem cell transplant after maximal surgery. At 1-3-5 years, the global overall survival (OS) was 90, 70, and 70% and the progression-free survival (PFS) was 80-60 and 60%. In all the patients, the copy number variants (CNVs) profile was analyzed using the SNP/CGH array approach. To investigate the clinical relevance of germline SMARCB1 mutation in AT/RT patients, we performed sequence analysis of the coding regions. The two patients with AT/RT were found to have germline SMARCB1 mutations. No BRAF mutations were found, and only NTRK gene fusion was present in one patient. We also have examined the association with OS and PFS and different histological subtypes of infant CNS proving that high-grade astrocytoma has better overall survival than other tumor types (p: 0.007 and p: 0.0590). Conclusion: High-dose chemotherapy regimen represents a valid therapeutic approach for congenital brain tumors with a high rate of response. The molecular analysis has to be analyzed in all infants' brain tumor types. High-grade gliomas are characterized by a better prognosis than other histologies of infant CNS.

P14.46 SUBEPENDYMAL GIANT CELLS ASTROCYTOMA (SEGA) IN TUBEROUS SCLEROSIS COMPLEX (TSC): A SERIES OF 31 PATIENTS

Background

Subependymal Giant Cells Astrocytomas (SEGAs) are characteristic of Tuberous Sclerosis Complex (TSC). They are usually benign tumors but may rapidly grow and cause hydrocephalus and raised intracranial pressure. Surgery is mandatory for large and symptomatic SEGAs

METHODS

31 patients harboring SEGAs in TSC were admitted for surgery. The main indications for surgery were tumor size and location, tumoral growth and cystization/hemorrhage, and hydrocephalus. In presence of symptomatic hydrocephalus firts surgery aimed to reduce intracranial pressure

RESULTS

Forty-four surgeries were performed in 31 patients achieving Gross Total and Subtotal Removal in 36 and 8 patients respectively. Recurrences occurred in 11 patients; nine of them were reoperated while two were administered therapy with m-TOR pathway inhibitors. Surgical morbidity and mortality accounted for 22.7% and 2.3% respectively; hydrocephalus was the main complication. After an average follow-up of 5 years, 90% of patients had no evidence of the disease and most (93,3%) had a good clinical status after surgery; 12 out of 30 patients (40%) had a VP-shunt for hydrocephalus

Conclusions

GTR is feasible and represents the treatment of choice of SEGAs in TSC. Therapy with m-TOR pathway inhibitors is to be considered in selected patients and especially in recurrences of SEGAs

P08.03 Separation and divorce after the diagnosis of child’s brain tumor

BACKGROUND

The diagnosis of a child’s brain tumor is a terrible situation for every member of the family. Numerous are the case of separations and divorces in Italy after a diagnosis of a child’s cancer. In particular, it happens with parents of children affected with brain tumor, being the most frequent solid tumor and the first cause of a tumor child’s death. The crisis related to the discovery of a tumor consists of four phases: shock, reaction, processing and re-orientation. It can happen that the diagnosis, experienced as a traumatic experience, can unite the family members as well as separate them. If there is already a process of family disintegration, a trauma can be a cause for breakup. The aim of our study was to investigate the possible correlation between brain tumor diagnosis in children and parental separations/divorces.

MATERIAL AND METHODS

We considered 427 patients afferent from 2012 to 2018 to the Neuro-Oncology Unit of the Meyer Children’s Hospital. Brain tumors are the 55–60% of all the tumors of our hospital, with an extra-regionality greater than 65%. The data analysis was conducted through information obtained directly from the families during follow-up visits or by telephone interviews.

RESULTS

Consistent with literature data in our series, the most frequent brain tumors were low-grade gliomas medulloblastomas, high-grade gliomas, ependymomas, midline diffuse gliomas, craniopharyngiomas, germ cell tumors and other rare pediatric tumors. The population was divided in 16 females and 18 males from different Italian regions: 65% from Central Italy, 23% from the South and Islands, 12% from the North. Data analysis showed 34 cases of separation and/or divorce, equal to 7% of our whole population, during treatment and more frequently at the end of treatment or after death. The median age of the 34 patients at the diagnosis of brain tumor was 9.5 years (range 1–19 years), with a higher percentage of cases of separations (41%) for parents of patients aged 10 years-14 years; 7 were the cases of separation and/or divorce when the diagnosis of brain tumor was made around 12–48 months after the child birth.

CONCLUSION

The diagnosis of a child’s brain tumor can generate stress in the family leading to different reactions, such as conflicts between parents or a real family crisis. The results of our study suggest a possible correlation between the diagnosis of a child’s brain tumor and the cases of separation and/or divorce. High risk medulloblastomas and high-grade gliomas that are likely to have a shorter path due to the unfavorable prognosis of the disease, appear to be the pathologies more often related to situations of family disputes. However, further investigations are necessary to verify the trend emerged from our study respect to the normal population.

P04.08 The role of SCN1A in glioblastomas and mixed neuronal glial tumors of pediatric age

BACKGROUND

Low and high grade gliomas, are the most common pediatric central nervous system (CNS) tumors and they show an extremely broad range of clinical behavior. Pediatric glioma is distinct from its adult counterpart with different genetic/epigenetic profile and biological features. Recently, several studies have shown the involvement of voltage-gated Na+ channels (VGSC) in different types of cancer, including gliomas. VGSC are multimeric transmembrane complexes, responsible for membrane depolarization in excitable cells playing an important role also in cell proliferation, migration, apoptosis and differentiation. VGSC are therapeutic targets in cardiovascular and neurological disorders and, in cancers, they could be a novel target for the development of promising anticancer therapy

MATERIAL AND METHODS

Firstly, we explored the genetic background of 9 pediatric glioblastomas (1–9 pGBMs), through whole-exome sequencing (WES) using HiSeq1000 platform (Illumina) with paired-end approach. On the basis of our results, we extended our study in another group of 16 epileptogenic mixed neuronal-glial tumors of pediatric age, (WHO grade I and II), through an amplicon approach (TSCA) using MiniSeq System platform (Illumina)

RESULTS

We identified variants in SCN1A gene in 3/9 pGBMs: case 3 had c.5782C>G in tumor and blood; case 5 showed c.2278G>T and two mosaic variants (c.5933C>T, 22% and c.4942C>T, 14%); case 6 showed c.667G>T variant only in tumor, and not in other non tumoral tissues (blood, urine and buccal swab). No variants in SCN1A were identified in a group of 16 pediatric mixed gliomas

CONCLUSION

In this study, we explore the genetic background of two groups of pediatric neuroepithelial brain tumors, through Next generation sequencing approach. We identified only in pGBMs variants in SCN1A gene that encoded for VGSCs and is involved in a spectrum of early-onset epileptic encephalopathies. None of our mutated patients showed history of epilepsy. Now, it is not clear the significance of these variants in pGBMs but interestingly, these variants are present in pGBM and not in mixed gliomas. Further studies on a big cohort of patients are needed to establish if they could play a role in pGBMs aggressiveness, migration and progression. Moreover, VGSCs could be a pharmacological target in pGBMs treatment

A microRNA profile of pediatric glioblastoma: The role of NUCKS1 upregulation

MicroRNAs (miRNAs/miRs) are a novel class of gene regulators that may be involved in tumor chemoresistance. Recently, specific miRNA expression profiles have been identified in adult glioblastoma (aGBM), but there are only limited data available on the role of miRNAs in pediatric GBM (pGBM). In the present study, the expression profile of miRNAs was examined in seven pGBMs and three human GBM cell lines (U87MG, A172 and T98G), compared with a non-tumoral pool of pediatric cerebral cortex samples by microarray analysis. A set of differentially expressed miRNAs was identified, including miR-490, miR-876-3p, miR-876-5p, miR-448 and miR-137 (downregulated), as well as miR-501-3p (upregulated). Through bioinformatics analysis, a series of target genes was predicted. In addition, similar gene expression patterns in pGBMs and cell lines was confirmed. Of note, drug resistant T98G cells had upregulated nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) expression, a protein overexpressed in many tumors that serves an important role in cell proliferation and progression. On the basis of the present preliminary report, it could be intriguing to further investigate the relationship between each of the identified differentially expressed miRNAs and NUCKS1, in order to clarify their involvement in the multi-drug resistance mechanism of pGBMs.

Aldoxorubicin and Temozolomide combination in a xenograft mice model of human glioblastoma

Glioblastoma Multiforme (GBM) is still an incurable disease. The front-line Temozolomide (TMZ)-based therapy suffers from poor efficacy, underlining the need of new therapies.

Preclinically, Aldoxorubicin (Aldox), a novel prodrug of Doxorubicin (Dox), has been successfully tested against GBM, encouraging the study of its association with other agents.

For the first time, we evaluated the effectiveness of Aldox combined to TMZ in preclinical models of GBM.

Our in vitro results demonstrated that the anti–glioma effect of Aldox was more marked than TMZ and their combination increased the killing effect of the anthracycline in TMZ-resistant GBM cells. Moreover, unlike Dox, Aldox was able to accumulate in P-glycoprotein (P-gp)-overexpressed cells due to a negative regulation of the P-gp function.

We also compared efficacy and safety of weekly administrations of Aldox (16 mg/kg), with or without TMZ (0.9 mg/kg, daily injections), in the U87 xenograft mouse model.

Aldox therapy induced a moderate tumor volume inhibition (TVI) and an increased survival rate (+12.5% vs vehicle). On the other hand, when combined to TMZ, Aldox caused a significant TVI (P=0.0175 vs vehicle) and delayed the mortality during the experimental period, although TVI and endpoint survival percentage (+37.5% vs vehicle) were not significantly different from TMZ alone.

Our preliminary data showed that Aldox exerts anti–glioma effects in vitro and in vivo. It also enhances its antitumor activity when combined with TMZ, resulting in a superior efficacy compared to the single agents, without adverse side effects.

Glioblastoma Chemoresistance: The Double Play by Microenvironment and Blood-Brain Barrier

For glioblastoma, the tumor microenvironment (TME) is pivotal to support tumor progression and therapeutic resistance. TME consists of several types of stromal, endothelial and immune cells, which are recruited by cancer stem cells (CSCs) to influence CSC phenotype and behavior. TME also promotes the establishment of specific conditions such as hypoxia and acidosis, which play a critical role in glioblastoma chemoresistance, interfering with angiogenesis, apoptosis, DNA repair, oxidative stress, immune escape, expression and activity of multi-drug resistance (MDR)-related genes. Finally, the blood brain barrier (BBB), which insulates the brain microenvironment from the blood, is strongly linked to the drug-resistant phenotype of glioblastoma, being a major physical and physiological hurdle for the delivery of chemotherapy agents into the brain. Here, we review the features of the glioblastoma microenvironment, focusing on their involvement in the phenomenon of chemoresistance; we also summarize recent advances in generating systems to modulate or bypass the BBB for drug delivery into the brain. Genetic aspects associated with glioblastoma chemoresistance and current immune-based strategies, such as checkpoint inhibitor therapy, are described too.

Correction to: Results of nimotuzumab and vinorelbine, radiation and re-irradiation for diffuse pontine glioma in childhood

The therapeutic experience reported in the paper was conceived after the use of nimotuzumab and radiotherapy (BSCPED-05 international multicentric trial, EUDRACT 2005-003100-11) in 2009 when we decided to explore the activity of the same combination plus vinorelbine (see the paper for the rationale).

Sirolimus in Infants with Multiple Cardiac Rhabdomyomas Associated with Tuberous Sclerosis Complex

INTRODUCTION

Cardiac rhabdomyomas represent a frequent manifestation of tuberous sclerosis. Tumor growth, mainly prenatally, can result in intrauterine fetal or neonatal deaths in almost 10% of patients.

CASE REPORT

We treated 3 consecutive infants aged less than 12 months with sirolimus, an oral mTOR inhibitor. All patients achieved significant reductions in cardiac rhabdomyomas. A complete response was documented in 2 patients, while a partial response with tumor debulking greater than 50% was seen in the other one. The median time to best cardiac response was 1.9 months in all patients, and 3.3 months in those with complete response. The side effects profile was acceptable.

CONCLUSION

Sirolimus may have a significant role in promoting natural regression of cardiac rhabdomyomas. Prospective clinical trials are needed.

The High Prevalence of Thermolabile 5-10 Methylenetetrahydrofolate Reductase (MTHFR) in Italians Is not Associated to an Increased Risk for Coronary Artery Disease (CAD)

Mild hyperhomocysteinemia was found to be related to venous thrombosis, cerebrovascular and coronary artery disease (CAD). Some recent studies suggested that a mutation in the gene encoding for 5-10 methylenetetrahydrofolate reductase (MTHFR), due to a transition C→ at nucleotide 677, is a genetic risk factor for vascular disease. However, several further studies could not confirm this association.

We investigated 84 patients with CAD who underwent percutaneous transluminal coronary angioplasty (PTCA) and 106 healthy subjects.

The prevalence of the mutated homozygous genotype was much higher than in other Italian populations, Europeans or other major human groups, but no excess of the Val/Val homozygotes was found in patients (28.5%) with respect to healthy subjects (30.2%). Mutated homozygous MTHFR genotype (+/+) was not found to be related to the clinical manifestations of CAD, to the prevalence of the common risk factors and to the rate of restenosis.

In conclusion, thermolabile MTHFR does not appear to be associated “per se” with the risk for CAD or for restenosis after PTCA. The high frequency of the +/+ genotype in our Italian population (from Tuscany) confirms a wide macroheterogeneity and suggests a microheterogeneity in the genotype frequencies of the different ethnic populations.

Preliminary data of this paper were selected for an Oral Communication at the XVIth ISTH Congress.