Prospective biomarker study in newly diagnosed glioblastoma: Cyto-C clinical trial.

BACKGROUND: Glioblastoma (GBM) has a 5-year survival rate of 3%-5%. GBM treatment includes maximal resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ). Cytochrome C oxidase (CcO) is a mitochondrial enzyme involved in the mechanism of resistance to TMZ. In a prior retrospective trial, CcO activity in GBMs inversely correlated with clinical outcome. The current Cyto-C study was designed to prospectively evaluate and validate the prognostic value of tumor CcO activity in patients with newly diagnosed primary GBM, and compared to the known prognostic value of MGMT promoter methylation status. METHODS: This multi-institutional, blinded, prospective biomarker study enrolled 152 patients with newly diagnosed GBM who were to undergo surgical resection and would be candidates for standard of care. The primary end point was overall survival (OS) time, and the secondary end point was progression-free survival (PFS) time. Tumor CcO activity and MGMT promoter methylation status were assayed in a centralized laboratory. RESULTS: OS and PFS did not differ by high or low tumor CcO activity, and the prognostic validity of MGMT promoter methylation was confirmed. Notably, a planned exploratory analysis suggested that the combination of low CcO activity and MGMT promoter methylation in tumors may be predictive of long-term survival. CONCLUSIONS: Tumor CcO activity alone was not confirmed as a prognostic marker in GBM patients. However, the combination of low CcO activity and methylated MGMT promoter may reveal a subgroup of GBM patients with improved long-term survival that warrants further evaluation. Our work also demonstrates the importance of performing large, multi-institutional, prospective studies to validate biomarkers. We also discuss lessons learned in assembling such studies.

Rare Ameloblastic Carcinoma Metastasis to the Cervical Spine: A Case Report.

BACKGROUND AND IMPORTANCE: Ameloblastic carcinoma (AC) is a malignant neoplasm of epithelial origin that typically arises from the mandible or maxilla. It represents approximately 2% of all odontogenic tumors. Gross total resection is the surgical goal given AC's aggressiveness and propensity for recurrence. We present the first reported AC metastasis to the cervical spine. CLINICAL PRESENTATION: A 61-yr-old African American female with a history of AC of bilateral mandibles and lung metastases presented with neck pain and right arm weakness progressive over several months. Cervical spine imaging demonstrated a cervical 3 pathological fracture with severe anterior vertebral body compression and resultant cervical 2-3 kyphotic deformity and bony retropulsion causing severe cord compression. The patient underwent a cervical 3 corpectomy and cervical 2-4 anterior fixation followed by a cervical 3 laminectomy and cervical 2-5 dorsal internal fixation and fusion. Postoperatively, the patient's neurological exam remained stable and imaging showed improved spinal alignment and appropriate anterior and posterior instrumentation. Unfortunately, the patient thereafter suffered a decline in performance status and progression of lung metastatic disease. Her oncology team is considering chemotherapy and stereotactic radiosurgery, but her prognosis remains grim. CONCLUSION: AC is a rare and aggressive pathology with a poor prognosis despite multimodal therapy. We present the first case of AC metastatic spread to the spine. We aim to bring this pathology to the attention of our worldwide neurosurgical colleagues and share our surgical approach and multidisciplinary management to assist those who may encounter this pathology in the future.

Cerebellar talcosis following posterior reversible encephalopathy syndrome in an intravenous methamphetamine abuser.

BACKGROUND: Intravenous (IV) methamphetamine abuse is associated with a variety of short- and long-term effects on the nervous system, some of which have yet to be fully elucidated. One known systemic complication that has not been described in nervous system tissues is the deposition of substrate crystals contained in injectable drugs. CASE DESCRIPTION: An unusual case is presented of a 35-year-old active IV methamphetamine abuser with posterior reversible encephalopathy syndrome (PRES) who subsequently developed multifocal bilateral cerebellar enhancing lesions and leptomeningeal enhancement due to biopsy-proven crystalline deposits. CONCLUSION: Although large crystalline substances will not normally penetrate the blood-brain barrier (BBB), during a state of BBB compromise such as with PRES, talc deposition may occur in the central nervous system.

NKX3.1 Identifies Prostatic Origin of Dural Metastasis in the Setting of Negative Prostate-Specific Antigen Stain.

No clear guidelines exist for the appropriate diagnostic workup of an intracranial mass suspected to be a metastasis from unknown primary origin. Dural metastasis from prostatic origin is very rare. Patients with a known history of metastatic prostate cancer who present with a newly discovered lesion on brain imaging require neurosurgical biopsy to confirm diagnosis prior to initiating treatment. Intracranial metastasis from prostate cancer is rare, and dural metastasis is rarer than intraparenchymal metastasis. Current consensus guidelines support immunohistochemical staining with classic markers such as prostate-specific antigen (PSA) to identify prostatic origin. However, PSA detection of prostate metastases declines with higher Gleason scores and in patients undergoing androgen deprivation therapy. NKX3.1 is another stain that is highly sensitive and specific for prostate. Our patient was a 54-year-old man with a history of metastatic prostate cancer who presented with new-onset seizures. Brain imaging revealed a dural-based lesion with surrounding vasogenic edema and midline shift. The patient underwent resection of the lesion, which was stained with multiple cancer markers. Prostate-specific antigen was negative, but NKX3.1 was positive indicating a prostatic origin for the mass. He underwent a craniectomy to remove the lesion and was given steroids. However, he succumbed to his illness several months later. Here, we document the first report to our knowledge of a patient with prostate metastasis to the dura that is PSA negative, but NKX3.1 positive.

RANKLed by the Complexity of Signaling in Breast Cancer Metastasis to the Brain.

BACKGROUND: Receptor activator of nuclear factor κB (RANK) and its ligand, RANKL, are essential for mammary gland development and play a vital role in breast carcinogenesis. RANKL-RANK signaling also drives thermoregulation and modulates inflammatory activation in the brain. The expression of RANKL in primary breast cancer (BC) has been negatively associated with brain metastases, while significantly higher levels of RANK are seen in BC with brain metastases. We examined the expression of RANK and RANKL in BC metastasis to the brain. PATIENTS AND METHODS: We examined the expression of RANK and RANKL in 40 cases of BC metastasis to the brain. RESULTS: RANK was variably expressed in BC cells but minimally expressed in the adjacent brain parenchyma. In contrast, the expression of RANKL was minimal in metastatic BC but highly variable in tumoral stroma. RANKL expression in normal brain stroma obtained during autopsy was negligible. Histologic grade and BC subtypes were not significantly associated with RANK expression in metastatic BC. A significant negative correlation between RANK in metastatic BC and RANKL in tumoral stroma was identified (P < .001). CONCLUSION: RANK expressed by primary BC and RANKL detected in the tumor microenvironment together participate in cancer development, while the same principle may operate at distant sites. Further investigation is necessary to provide additional insight into the role of the RANKL-RANK pathway in BC progression and to investigate the potential efficacy of therapeutic strategies targeting these molecules in BC metastasis to the brain.

Targeting glioma-initiating cells via the tyrosine metabolic pathway.

OBJECTIVE: Despite an aggressive multimodal therapeutic regimen, glioblastoma (GBM) continues to portend a grave prognosis, which is driven in part by tumor heterogeneity at both the molecular and cellular levels. Accordingly, herein the authors sought to identify metabolic differences between GBM tumor core cells and edge cells and, in so doing, elucidate novel actionable therapeutic targets centered on tumor metabolism. METHODS: Comprehensive metabolic analyses were performed on 20 high-grade glioma (HGG) tissues and 30 glioma-initiating cell (GIC) sphere culture models. The results of the metabolic analyses were combined with the Ivy GBM data set. Differences in tumor metabolism between GBM tumor tissue derived from within the contrast-enhancing region (i.e., tumor core) and that from the peritumoral brain lesions (i.e., tumor edge) were sought and explored. Such changes were ultimately confirmed at the protein level via immunohistochemistry. RESULTS: Metabolic heterogeneity in both HGG tumor tissues and GBM sphere culture models was identified, and analyses suggested that tyrosine metabolism may serve as a possible therapeutic target in GBM, particularly in the tumor core. Furthermore, activation of the enzyme tyrosine aminotransferase (TAT) within the tyrosine metabolic pathway influenced the noted therapeutic resistance of the GBM core. CONCLUSIONS: Selective inhibition of the tyrosine metabolism pathway may prove highly beneficial as an adjuvant to multimodal GBM therapies.

An Update on Neurofibromatosis Type 1-Associated Gliomas.

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that affects children and adults. Individuals with NF1 are at high risk for central nervous system neoplasms including gliomas. The purpose of this review is to discuss the spectrum of intracranial gliomas arising in individuals with NF1 with a focus on recent preclinical and clinical data. In this review, possible mechanisms of gliomagenesis are discussed, including the contribution of different signaling pathways and tumor microenvironment. Furthermore, we discuss the recent notable advances in the developing therapeutic landscape for NF1-associated gliomas including clinical trials and collaborative efforts.

Chondroblastoma-like mass of the temporal bone, secondary aneurysmal bone cyst, and intracerebral hemorrhage in a patient with cardiofaciocutaneous syndrome: case report.

Cardiofaciocutaneous syndrome (CFCS) is a rare developmental disorder that is phenotypically similar to Noonan syndrome and is associated with mutations in BRAF, MEK1, MEK2, and KRAS. The relationship between malignancy risk and CFCS is unclear with few cases published in the literature. The purpose of this paper is to describe the case of a patient with CFCS presenting in extremis as a result of a large intracerebral hemorrhage arising from a temporal bone mass with histopathology most consistent with chondroblastoma and secondary aneurysmal bone cyst. This is the first case to document an association between CFCS and chondroblastoma.

Myristoylated alanine-rich C-kinase substrate effector domain phosphorylation regulates the growth and radiation sensitization of glioblastoma.

Glioblastoma harbors frequent alterations in receptor tyrosine kinases, phosphatidylinositol­3 kinase (PI3K) and phosphatase and tensin homolog (PTEN) that dysregulate phospholipid signaling driven tumor proliferation and therapeutic resistance. Myristoylated alanine­rich C­kinase substrate (MARCKS) is a 32 kDa intrinsically unstructured protein containing a polybasic (+13) effector domain (ED), which regulates its electrostatic sequestration of phospholipid phosphatidylinositol (4,5)­bisphosphate (PIP2), and its binding to phosphatidylserine, calcium/calmodulin, filamentous actin, while also serving as a nuclear localization sequence. MARCKS ED is phosphorylated by protein kinase C (PKC) and Rho­associated protein kinase (ROCK) kinases; however, the impact of MARCKS on glioblastoma growth and radiation sensitivity remains undetermined. In the present study, using a tetracycline­inducible system in PTEN­null U87 cells, we demonstrate that MARCKS overexpression suppresses growth and enhances radiation sensitivity in vivo. A new image cytometer, Xcyto10, was utilized to quantify differences in MARCKS ED phosphorylation on localization and its association with filamentous actin. The overexpression of the non­phosphorylatable ED mutant exerted growth­suppressive and radiation­sensitizing effects, while the pseudo­phosphorylated ED mutant exhibited an enhanced colony formation and clonogenic survival ability. The identification of MARCKS protein­protein interactions using co­immunoprecipitation coupled with tandem mass spectrometry revealed novel MARCKS­associated proteins, including importin­ß and ku70. On the whole, the findings of this study suggest that the determination of the MARCKS ED phosphorylation status is essential to understanding the impact of MARCKS on cancer progression.

Chromodomain Helicase DNA-Binding Protein 7 Is Suppressed in the Perinecrotic/Ischemic Microenvironment and Is a Novel Regulator of Glioblastoma Angiogenesis.

Tumorigenic and non-neoplastic tissue injury occurs via the ischemic microenvironment defined by low oxygen, pH, and nutrients due to blood supply malfunction. Ischemic conditions exist within regions of pseudopalisading necrosis, a pathological hallmark of glioblastoma (GBM), the most common primary malignant brain tumor in adults. To recapitulate the physiologic microenvironment found in GBM tumors and tissue injury, we developed an in vitro ischemic model and identified chromodomain helicase DNA-binding protein 7 (CHD7) as a novel ischemia-regulated gene. Point mutations in the CHD7 gene are causal in CHARGE syndrome (a developmental disorder causing coloboma, heart defects, atresia choanae, retardation of growth, and genital and ear anomalies) and interrupt the epigenetic functions of CHD7 in regulating neural stem cell maintenance and development. Using our ischemic system, we observed microenvironment-mediated decreases in CHD7 expression in brain tumor-initiating cells and neural stem cells. Validating our approach, CHD7 was suppressed in the perinecrotic niche of GBM patient and xenograft sections, and an interrogation of patient gene expression datasets determined correlations of low CHD7 with increasing glioma grade and worse patient outcomes. Segregation of GBM by molecular subtype revealed a novel observation that CHD7 expression is elevated in proneural versus mesenchymal GBM. Genetic targeting of CHD7 and subsequent gene ontology analysis of RNA sequencing data indicated angiogenesis as a primary biological function affected by CHD7 expression changes. We validated this finding in tube-formation assays and vessel formation in orthotopic GBM models. Together, our data provide further understanding of molecular responses to ischemia and a novel function of CHD7 in regulating angiogenesis in both neoplastic and non-neoplastic systems. Stem Cells 2019;37:453-462.

Pathologic Predictors of Local Recurrence in Atypical Meningiomas Following Gross Total Resection.

PURPOSE: To assess the local recurrence rate of gross totally resected atypical meningiomas and evaluate for pathologic predictors of recurrence. METHODS AND MATERIALS: All patients meeting the 2016 World Health Organization grade 2 meningioma criteria who received gross total resection were included in this retrospective analysis. A neuropathologist re-reviewed all surgical specimens for the following pathologic factors: brain invasion, macronuclei, necrosis, sheeting architecture, hypercellularity, high nuclear to cytoplasmic ratio, Ki67 proliferative index, mitotic number, and choroid or clear cell histology. Local recurrence and salvage therapy were recorded. RESULTS: Ninety-seven patients met the inclusion criteria and had a median radiographic follow-up of 53 months (range, 3-153). Necrosis was present in 41 specimens (42%), and brain invasion occurred in 30 (31%). Seventy-six patients (78%) had 3 of 5 World Health Organization grade 2 qualifying atypical features. Median mitotic number and Ki67 index were 3 (0-12) and 15 (2%-55%), respectively. Only Ki67 proliferative index and mitotic number predict for local recurrence. The Kaplan-Meier estimate of local recurrence was 30.3% at 3 years. CONCLUSIONS: In this cohort of gross totally resected atypical meningioma followed with observation, local recurrence occurred in 30.3% at 3 years. Ki67 index and mitotic number predict for local failure and could help stratify patients who would benefit from adjuvant therapy.

Long-Term Survival After Transformation of an Adrenocorticotropic Hormone-Secreting Pituitary Macroadenoma to a Silent Corticotroph Pituitary Carcinoma.

BACKGROUND: Pituitary carcinomas are rare and aggressive neoplasms that despite current treatment regimens continue to have a poor prognosis. Adrenocorticotrophic hormone pituitary tumors have been shown to alter their clinical manifestations with conversion to Cushing disease and silent types. CASE DESCRIPTION: The purpose of this paper is to present the first documented case of an adrenocorticotrophic hormone-secreting pituitary adenoma with Cushing disease that differentiated into a silent corticotroph pituitary carcinoma with metastases to distant sites in the central nervous system. CONCLUSIONS: This patient was later treated with radiotherapy, temozolomide, and bevacizumab, with 8 years of progression-free survival.

Characterization of iPSCs derived from low grade gliomas revealed early regional chromosomal amplifications during gliomagenesis.

INTRODUCTION: IDH1 mutation has been identified as an early genetic event driving low grade gliomas (LGGs) and it has been proven to exerts a powerful epigenetic effect. Cells containing IDH1 mutation are refractory to epigenetical reprogramming to iPSC induced by expression of Yamanaka transcription factors, a feature that we employed to study early genetic amplifications or deletions in gliomagenesis. METHODS: We made iPSC clones from freshly surgically resected IDH1 mutant LGGs by forced expression of Yamanaka transcription factors. We sequenced the IDH locus and analyzed the genetic composition of multiple iPSC clones by array-based comparative genomic hybridization (aCGH). RESULTS: We hypothesize that the primary cell pool isolated from LGG tumor contains a heterogeneous population consisting tumor cells at various stages of tumor progression including cells with early genetic lesions if any prior to acquisition of IDH1 mutation. Because cells containing IDH1 mutation are refractory to reprogramming, we predict that iPSC clones should originate only from LGG cells without IDH1 mutation, i.e. cells prior to acquisition of IDH1 mutation. As expected, we found that none of the iPSC clones contains IDH1 mutation. Further analysis by aCGH of the iPSC clones reveals that they contain regional chromosomal amplifications which are also present in the primary LGG cells. CONCLUSIONS: These results indicate that there exists a subpopulation of cells harboring gene amplification but without IDH1 mutation in the LGG primary cell pool. Further analysis of TCGA LGG database demonstrates that these regional chromosomal amplifications are also present in some cases of low grade gliomas indicating they are reoccurring lesions in glioma albeit at a low frequency. Taken together, these data suggest that regional chromosomal alterations may exist prior to the acquisition of IDH mutations in at least some cases of LGGs.

Reactive species balance via GTP cyclohydrolase I regulates glioblastoma growth and tumor initiating cell maintenance.

Background: Depending on the level, differentiation state, and tumor stage, reactive nitrogen and oxygen species inhibit or increase cancer growth and tumor initiating cell maintenance. The rate-limiting enzyme in a pathway that can regulate reactive species production but has not been thoroughly investigated in glioblastoma (GBM; grade IV astrocytoma) is guanosine triphosphate (GTP) cyclohydrolase 1 (GCH1). We sought to define the role of GCH1 in the regulation of GBM growth and brain tumor initiating cell (BTIC) maintenance. Methods: We examined GCH1 mRNA and protein expression in patient-derived xenografts, clinical samples, and glioma gene expression datasets. GCH1 levels were modulated using lentiviral expression systems, and effects on cell growth, self-renewal, reactive species production, and survival in orthotopic patient-derived xenograft models were determined. Results: GCH1 was expressed in GBMs with elevated but not exclusive RNA and protein levels in BTICs in comparison to non-BTICs. Overexpression of GCH1 in GBM cells increased cell growth in vitro and decreased survival in an intracranial GBM mouse model. In converse experiments, GCH1 knockdown with short hairpin RNA led to GBM cell growth inhibition and reduced self-renewal in association with decreased CD44 expression. GCH1 was critical for controlling reactive species balance, including suppressing reactive oxygen species production, which mediated GCH1 cell growth effects. In silico analyses demonstrated that higher GCH1 levels in glioma patients correlate with higher glioma grade, recurrence, and worse survival. Conclusions: GCH1 expression in established GBMs is pro-tumorigenic, causing increased growth due, in part, to promotion of BTIC maintenance and suppression of reactive oxygen species.

Addition of carbonic anhydrase 9 inhibitor SLC-0111 to temozolomide treatment delays glioblastoma growth in vivo.

Tumor microenvironments can promote stem cell maintenance, tumor growth, and therapeutic resistance, findings linked by the tumor-initiating cell hypothesis. Standard of care for glioblastoma (GBM) includes temozolomide chemotherapy, which is not curative, due, in part, to residual therapy-resistant brain tumor-initiating cells (BTICs). Temozolomide efficacy may be increased by targeting carbonic anhydrase 9 (CA9), a hypoxia-responsive gene important for maintaining the altered pH gradient of tumor cells. Using patient-derived GBM xenograft cells, we explored whether CA9 and CA12 inhibitor SLC-0111 could decrease GBM growth in combination with temozolomide or influence percentages of BTICs after chemotherapy. In multiple GBMs, SLC-0111 used concurrently with temozolomide reduced cell growth and induced cell cycle arrest via DNA damage in vitro. In addition, this treatment shifted tumor metabolism to a suppressed bioenergetic state in vivo. SLC-0111 also inhibited the enrichment of BTICs after temozolomide treatment determined via CD133 expression and neurosphere formation capacity. GBM xenografts treated with SLC-0111 in combination with temozolomide regressed significantly, and this effect was greater than that of temozolomide or SLC-0111 alone. We determined that SLC-0111 improves the efficacy of temozolomide to extend survival of GBM-bearing mice and should be explored as a treatment strategy in combination with current standard of care.

Hu antigen R (HuR) multimerization contributes to glioma disease progression.

Among primary brain cancers, gliomas are the most deadly and most refractory to current treatment modalities. Previous reports overwhelmingly support the role of the RNA-binding protein Hu antigen R (HuR) as a positive regulator of glioma disease progression. HuR expression is consistently elevated in tumor tissues, and a cytoplasmic localization appears essential for HuR-dependent oncogenic transformation. Here, we report HuR aggregation (multimerization) in glioma and the analysis of this tumor-specific HuR protein multimerization in clinical brain tumor samples. Using a split luciferase assay, a bioluminescence resonance energy transfer technique, and site-directed mutagenesis, we examined the domains involved in HuR multimerization. Results obtained with the combination of the split HuR luciferase assay with the bioluminescence resonance energy transfer technique suggested that multiple (at least three) HuR molecules come together during HuR multimerization in glioma cells. Using these data, we developed a model of HuR multimerization in glioma cells. We also demonstrate that exposing glioma cells to the HuR inhibitor tanshinone group compound 15,16-dihydrotanshinone-I or to the newly identified compound 5 disrupts HuR multimerization modules and reduces tumor cell survival and proliferation. In summary, our findings provide new insights into HuR multimerization in glioma and highlight possible pharmacological approaches for targeting HuR domains involved in cancer cell-specific multimerization.

Primary CNS Nonamyloidogenic Light Chain Deposition Disease: Case Report and Brief Review.

The true incidence of light chain deposition disease (LCDD) restricted to the central nervous system (CNS) is unknown. To our knowledge only 7 cases of LCDD restricted to the brain have been previously reported. We herein describe an unusual example. A 44-year-old man presented with a history of ischemic retinopathy in 2004 and left lower extremity hypoesthesia in 2007 that progressed gradually to left-sided weakness and numbness in the 2 years prior to his hospitalization in 2015. A stereotactic brain biopsy was performed, displaying nonspecific hyaline deposits of amorphous "amyloid-like" material involving deep brain white matter and vessels. These were Congo red negative and were accompanied by a sparse lymphoplasmacytic infiltrate. Plasma cells demonstrated kappa light chain class restriction by chromogenic in situ hybridization (CISH). There was patchy reactivity with kappa immunohistochemistry in the amorphous deposits. A diagnosis of light chain deposition disease was made. Subsequent systemic myeloma and lymphoma workups were negative. Previously reported cases have included men and women, spanning the ages of 19 and 72 years, often presenting with hemiparesis, hypoesthesia, or seizures. Deposits have been reported in the cerebrum and cerebellum. T2/FLAIR (fluid attenuation inversion recovery) changes are usual, but lesions may or may not produce contrast enhancement. The light chain deposition may be of kappa or lambda class. Most lesions have been accompanied by local lymphoid and/or plasma cell infiltrates exhibiting light chain restriction of the same class as the deposits. In summary, LCDD limited to the CNS is a rare lesion consisting of deposition of amyloid-like, but Congo red-negative monotypic light chain usually produced by local lymphoplasmacytic infiltrates.

Key rates for the grades and transformation ability of glioma: model simulations and clinical cases.

Tumor progression to higher grade is a fundamental property of cancer. The malignant advancement of the pathological features may either develop during the later stages of cancer growth (natural evolution) or it may necessitate new mutations or molecular events that alter the rates of growth, dispersion, or neovascularization (transformation). Here, we model the pathological and radiological features of grades 2-4 gliomas at the times of diagnosis and death and study grade development and the progression to higher grades. We perform a retrospective review of clinical cases based on model predictions. Simulations uncover two unusual patterns of glioma progression, which are supported by clinical cases: (1) some grades 2 and 3 gliomas lack the ability of progression to higher grades, and (2) grade 3 glioma may evolve to GBM in a few weeks. All 13 gliomas that recurred at the same grade carry either the IDH1-R132H or the ATRX mutation. All (five of five) grade 3 tumors are 1p/19q co-deleted, IDH1-R132H mutated and ATRX wt. Furthermore, three of seven grade 2 gliomas are both IDH1-R132H mutated and ATRX mutated. Simulations replicate the good prognosis of secondary GBM. The results support the hypothesis that constant rates of dispersion, proliferation, and angiogenesis prescribe either a natural evolution or the inability to progress to higher grades. Furthermore, the accrual of molecular events that change a tumor's ability to infiltrate, proliferate or neovascularize may transform the glioma either into a more aggressive tumor at the same grade or elevate its grade.