Integrated (epi)-Genomic Analyses Identify Subgroup-Specific Therapeutic Targets in CNS Rhabdoid Tumors

We recently reported that atypical teratoid rhabdoid tumors (ATRTs) comprise at least two transcriptional subtypes with different clinical outcomes; however, the mechanisms underlying therapeutic heterogeneity remained unclear. In this study, we analyzed 191 primary ATRTs and 10 ATRT cell lines to define the genomic and epigenomic landscape of ATRTs and identify subgroup-specific therapeutic targets. We found ATRTs segregated into three epigenetic subgroups with distinct genomic profiles, SMARCB1 genotypes, and chromatin landscape that correlated with differential cellular responses to a panel of signaling and epigenetic inhibitors. Significantly, we discovered that differential methylation of a PDGFRB-associated enhancer confers specific sensitivity of group 2 ATRT cells to dasatinib and nilotinib, and suggest that these are promising therapies for this highly lethal ATRT subtype.

Molecular subgroups of atypical teratoid rhabdoid tumours in children: an integrated genomic and clinicopathological analysis

BACKGROUND

Rhabdoid brain tumours, also called atypical teratoid rhabdoid tumours, are lethal childhood cancers with characteristic genetic alterations of SMARCB1/hSNF5. Lack of biological understanding of the substantial clinical heterogeneity of these tumours restricts therapeutic advances. We integrated genomic and clinicopathological analyses of a cohort of patients with atypical teratoid rhabdoid tumours to find out the molecular basis for clinical heterogeneity in these tumours.

METHODS

We obtained 259 rhabdoid tumours from 37 international institutions and assessed transcriptional profiles in 43 primary tumours and copy number profiles in 38 primary tumours to discover molecular subgroups of atypical teratoid rhabdoid tumours. We used gene and pathway enrichment analyses to discover group-specific molecular markers and did immunohistochemical analyses on 125 primary tumours to evaluate clinicopathological significance of molecular subgroup and ASCL1-NOTCH signalling.

FINDINGS

Transcriptional analyses identified two atypical teratoid rhabdoid tumour subgroups with differential enrichment of genetic pathways, and distinct clinicopathological and survival features. Expression of ASCL1, a regulator of NOTCH signalling, correlated with supratentorial location (p=0·004) and superior 5-year overall survival (35%, 95% CI 13-57, and 20%, 6-34, for ASCL1-positive and ASCL1-negative tumours, respectively; p=0·033) in 70 patients who received multimodal treatment. ASCL1 expression also correlated with superior 5-year overall survival (34%, 7-61, and 9%, 0-21, for ASCL1-positive and ASCL1-negative tumours, respectively; p=0·001) in 39 patients who received only chemotherapy without radiation. Cox hazard ratios for overall survival in patients with differential ASCL1 enrichment treated with chemotherapy with or without radiation were 2·02 (95% CI 1·04-3·85; p=0·038) and 3·98 (1·71-9·26; p=0·001). Integrated analyses of molecular subgroupings with clinical prognostic factors showed three distinct clinical risk groups of tumours with different therapeutic outcomes.

INTERPRETATION

An integration of clinical risk factors and tumour molecular groups can be used to identify patients who are likely to have improved long-term radiation-free survival and might help therapeutic stratification of patients with atypical teratoid rhabdoid tumours.

FUNDING

C17 Research Network, Genome Canada, b.r.a.i.n.child, Mitchell Duckman, Tal Doron and Suri Boon foundations.

Fusionless posterior hemivertebra resection in a 2-year-old child with 16 years follow-up

PURPOSE

We present the case of a 2-year-old patient with congenital scoliosis due to a lumbar hemivertebra. The current gold standard treatment of such an abnormality would be hemivertebra resection and short level posterior spinal fusion. However, due to the young age of the patient, we considered that application of a fusionless solution might offer advantages in terms of retaining normal segmental motion and the potential for growth.

METHODS

The incarcerated hemivertebra was resected and the facet joints of the neighbouring vertebrae were joined to create a new functional motion segment and correct the kyphoscoliotic deformity. Transpedicular screws were inserted on the convex side in L2 and L3 and a tension band was applied.

RESULTS

16 years after the surgery, the patient was completely pain-free, motion of the lumbar spine was preserved and the physiological curvatures were maintained.

CONCLUSION

To our knowledge a fusionless surgical solution for the treatment of a hemivertebra has never been described before. Although this is only a single case, the good result with a long follow-up suggests the technique is worthwhile considering when planning the treatment of a lumbar hemivertebra in very young children.

Expression of invasion-related extracellular matrix molecules in human glioblastoma versus intracerebral lung adenocarcinoma metastasis

Tumor cell invasion into the surrounding brain tissue is mainly responsible for the failure of radical surgical resection, with tumor recurrence in the form of microdisseminated disease. Extracellular matrix (ECM)-related molecules and their receptors predominantly participate in the invasion process, including cell adhesion to the surrounding microenvironment and cell migration. The extent of infiltration of the healthy brain by malignant tumors strongly depends on the tumor cell type. Malignant gliomas show much more intensive peritumoral invasion than do metastatic tumors. In this study, the mRNA expression of 30 invasion-related molecules (twenty-one ECM components, two related receptors, and seven ECM-related enzymes) was investigated by quantitative reverse transcriptase-polymerase chain reaction. Fresh frozen human tissue samples from glioblastoma (GBM), intracerebral lung adenocarcinoma metastasis, and normal brain were evaluated. Significant differences were established for 24 of the 30 molecules. To confirm our results at the protein level, immunohistochemical analysis of seven molecules was performed (agrin, neurocan, syndecan, versican, matrix metalloproteinase 2 [MMP-2], MMP-9, and hyaluronan). Determining the differences in the levels of invasion-related molecules for tumors of different origins can help to identify the exact molecular mechanisms that facilitate peritumoral infiltration by glioblastoma cells. These results should allow the selection of target molecules for potential chemotherapeutic agents directed against highly invasive malignant gliomas.

Epidural malignant lymphomas of the spine: collected experiences with epidural malignant lymphomas of the spinal canal and their treatment

STUDY DESIGN

Retrospective study of 13 patients treated by the authors.

OBJECTIVE

To examine the course of the disease of malignant lymphoma (ML) presenting in the epidural area of the spine.

SETTING

Department of Neurosurgery, Third Department of Internal Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.

SUBJECTS AND METHODS

The epidural presentation in eight patients was heralded by motor signs (paraparesis and plegia), in one by a lesion of the posterior columns of the spinal cord (ataxia), and in three by pain. One patient was free of complaints and symptoms. The affected epidural area was diagnosed previously by myelography and computerized tomography (CT), and later by magnetic resonance (MR), over the course of which the location was verified as thoracic in eight patients, cervical in one, and lumbar in four. The authors recommended surgical intervention in 9 out of 13 cases, in seven cases of Hodgkin's and six cases of non-Hodgkin's lymphoma. Seven patients were treated for recognized manifestations of malignant lymphoma while six were diagnosed by intraoperative-histological examination.

RESULTS AND CONCLUSION

The decompression operations for tumors resulted in limited improvement in seven patients (reduction in pain and return of ability to walk). Four patients were not operated on, two of which had significant improvement in their neurological symptoms. Paraparesis remained unchanged in one patient. One patient remained symptom-free. The authors emphasize the importance of interdisciplinary consultation and weighing individual priorities in the indications for operation on epidural ML.

Bilateral epilepsy surgery in a 4-year-old child

OBJECTIVE

Reports on bilateral epilepsy surgical interventions are anecdotal because of the possible neurological deficits caused by them.

METHODS

We report on a four-year-old amaurotic child with catastrophic epilepsy due to bilateral occipital cortical dysplasia. After video-EEG monitoring and intraoperative electrocorticography he underwent a two-step bilateral occipital lobectomy.

RESULTS

The first resection resulted in only temporary seizure cessation; however, he became seizure-free after the second operation (follow-up: 20 months).

CONCLUSION

Patients with catastrophic epilepsy due to bilateral epileptogenic lesions but without a high risk of additional postsurgical deficit may be good candidates for epilepsy surgery.

Antiorthostatic posture as an earth model of the effect of microgravity on the human body

We examined the horizontal and vertical component of diagonal optokinetic nystagmus (DOKN) in sitting posture and in the last 15 minutes of antiorthostatic posture at -30 degrees lasting 3 hours. The antiorthostatic posture is suited to the earthy model of the fluid shifting observed in microgravity. We found that the frequency of the vertical component of DOKN is rarer in antiorthostatic posture than in sitting posture. Moreover, the amplitude of the vertical component of DOKN is lower in antiorthostatic posture than is the amplitude of the horizontal component. According to our examinations, we suppose that the frequency and amplitude of vertical OKN are directed by different cerebral structures. Furthermore, we found that the heart rate becomes slower and the diastolic pressure is augmented after antiorthostatic posture and visual stimulation.

[Surgically treatable epilepsy--a review]

20-25% of epileptic patients do not become seizure free on adequate drug therapy. In 25-50% of patients with intractable epilepsy, the brain area responsible for seizures is well localizable and does not involve eloquent regions. In these patients, the surgical excision of the epileptic focus may lead to relief from seizures. In Hungary, there may be 5-6000 patients who needs an epilepsy surgery, but till now only 200 patients with chronic epilepsy underwent a surgical procedure. In the surgically remediable epilepsies, the operation is not a "ultima ratio". Concerning these syndromes, if 2-3 adequate antiepileptic drugs do not lead to seizure freedom within 1-3 years after the epilepsy onset, then a presurgical evaluation is necessary. The most common surgically remediable epilepsy is the temporal lobe epilepsy in which 60-90% of drug-resistant patients could be surgically cured. In lesional neocortical epilepsies 50-80% of patients become postoperatively seizure free. In childhood hemispheric epilepsies, the surgery could lead to seizure freedom in 70-80% of patients. The basic tools of the presurgical evaluation are the detailed history, the high resolution-MRI, the video-EEG monitoring, and the neuropsychological assessment. These investigation methods are usually enough to evaluate the necessity of the surgery and the postoperative outcome as well as to plan the localization and the extension of the resection. In some cases, ictal SPECT, PET, or video-EEG monitoring with intracranial electrodes could also be necessary in order to localize the epileptic focus.

Temporary cerebral histic hypoxia in simulated microgravity

The authors determined in their previous examinations that the vertical component of diagonal optokinetic nystagmus (DOKN) decreases considerably more in the conditions of hypoxia and antiorthostatic posture than does the horizontal component. Relying on these findings, they reasoned that the tectal and pretectal gaze centers, which organize vertical eye movement, are more sensitive to both hypoxia and antiorthostatic posture than is the pontine gaze center, which directs horizontal eye movement. In their present examinations, the authors sought to discover how cranial shifting of body fluids alters the DOKN and cardiopulmonary dynamics. They established that, at-30-degree antiorthostatic posture during 3 hours' loading, the diminution of pulse rate and systolic blood pressure is accompanied by continuous enhancement of diastolic blood pressure, diminishment of the carbonometric value, and augmentation of respiratory rate. The disturbances of DOKN, which mimicked previous similar findings under conditions of hypoxia and antiorthostatic posture, may be caused by the hypocapnia that is induced by antiorthostatic posture and that produces histic hypoxia. However, hypocapnia does not exclude the possibility of cerebrovascular injury, which was detected during animal experiments in microgravity or in simulated microgravity. To resolve this issue ultimately, further investigations are necessary.

[Chiari I. malformation, a new childhood disease?]

From July 1, 1994 to July 1, 1997 a total of 17 children with Chiari I malformation diagnosed by MRI was seen in our hospital. Six of them underwent craniocervical decompression and tonsilar resection. The major complaints of all these children were gait ataxia and persisting (longer than 6 month) headache, and one child had acutely presenting vertigo and problem of swallowing. The MRI showed that in all cases the tonsils were displaced below the level of CI. Hydrocephalus or syrinx was not seen. At surgery the tonsils were resected. All the patients can be considered cured and symptom free at an average follow up of 13 month.

[Neuronavigation in pediatric neurosurgery]

The precise orientation in the intracranial space is essential for the minimal invasive neurosurgical interventions. The CT and MR based neuro-navigation permits small, targeted exposures on the skull, and intraoperatively gives exact graphic-interactive guidance to the targeted intracranial lesions. The use of neuro-navigation can shorten the time of surgery and diminish the surgical mortality and morbidity. The favourable experiences of the first 21 neuro-navigation aided operations in pediatric patients performed in the National Institute of Neurosurgery (Budapest, Hungary) with the Vector Vision Neuro-navigation System (BrainLAB Gmbh, Germany) are discussed.

[Neuroendoscopic removal of a colloid cyst of the third ventricle]

The removal of the benign and only slightly symptomatic but by virtue of their localization potentially fatal lesions is a challenge for the neurosurgeons. Such cases demand a therapy without any postoperative morbidity. The neuroendoscopy meets these requirements and proves to be effective in more and more fields of the art. This article reports a case when colloid cyst was resected entirely by use of a neuroendoscope, firstly in Hungary.

Effect of microgravitation on the human equilibrium

The 38-year period of human space exploration has gained for us a lot of experience in the problem of space motion sickness. The authors collected some causes of space sickness from the literature and from their research results. We collaborated with the Soviet-Russian space researchers and elaborated those vestibular research methods that were carried out by human space missions in the Soviet-Russian space station, on Earth, and after flight: spontaneous eye movement, foveal and peripheral optokinetic nystagmus, and vestibular stimulation. Using an earthly model of the effect of microgravitation on the human body, we tried to provide explanations of the origin of space motion sickness.

[A new technic in the management of hydrocephalus: neuro-endoscopy]

Conventional valve shunting for treatment of hydrocephalus has a high rate of long-term complication. After a brief historical review of neurosurgical endoscopy the authors present the different indications and methods of neuroendoscopy. Between 1995 and 1997 twenty-two pediatric patients underwent endoscopic surgery at National Institute of Neurosurgery. Twelve of them had third ventriculo-cistemostomy, and cystic wall fenestration was performed in ten children. All but one patient benefited from this minimally invasive endoscopic technic. Minor transient complications were seen in three cases, and only one patient had long-term pupillary dilatation due to the surgical procedure.

Brain tumors during the first year of life

Of 1728 childhood brain tumors treated at the National Institute of Neurosurgery, Budapest during the years from 1954 until 1995, 83 of the affected children were younger than one year of age. Because of the advent of the CT and MRI scans in the last 11 years, 51 out of the 83 are presented, these being patients treated since these technological advances have been available. There was a male predominance, with 30 boys and 21 girls. Five of the 51 infants were diagnosed before two months of age. The ratio of supratentorial to infratentorial tumors was almost 1:1. Vomiting, alteration of psychomotor development, and macrocrania were the most common presenting features. Craniotomy and tumor debulking was performed in 85% of the children and 94% of the infants. The most frequent histological diagnosis was benign glioma, PNET, malignant glioma, and craniopharyngioma. The surgical mortality rate was 5% for the children and 13% for the infant group. All five neonates survived the surgical procedure. Radiation therapy was given in 29% of the children and in 7% of infants.

Multiple intracranial melanoma metastases treated with surgery and radiosurgery with long term control. A case report

A case of malignant melanoma with multiplex brain metastases is described, where both surgical and radiosurgical treatment was applied. Due to CNS manifestations the patient was operated on in two sessions. First the symptomatic large tumor was removed, and the other, small lesion which could not be reached from the same approach was operated later. The primary skin lesion was discovered and removed between the two operations. A CT scan three months after the second operation revealed recurrence at the site of the first operation, and the appearance of two new tumors. The intracranial neoplasms were treated in one session by stereotactic radiosurgery using a linear accelerator. Six months after this treatment a new skin lesion was removed and the patient received DTIC therapy. Successive CT scans after the irradiation showed a steady regression of the radiosurgically treated tumors, and more than one year after the irradiation no tumor could be detected on the CT scans.