The efficacy of immunohistochemistry in the diagnosis of molecular genetic alterations in central nervous system gliomas: Next-generation sequencing of 212 mutations in 112 patients.

Identification of molecular genetic alterations has become an important part of diagnosis and care of patients with brain tumors. Comparisons of immunohistochemistry (IHC) with DNA sequencing techniques have suggested that IHC is useful for identifying surrogates of mutations in gliomas; however, studies of the efficacy are relatively few. Our aim was to compare IHC in our neuropathology laboratory with a commercially available next-generation sequencing (NGS) platform, Tempus xT. We studied 212 immunohistochemically stained sections of gliomas to identify mutations of isocitrate dehydrogenase (IDH), p53, BRAF, the α-thalassemia/mental retardation syndrome X-linked protein (ATRX), and histone H3. Tempus xT NGS confirmed the IHC diagnosis of IDH1/R132H in 102 of 102 patients (100%), BRAF/V600E in 14 of 14 (100%) patients and H3/K27M in 10 of 10 (100%) patients. For p53, NGS confirmed the IHC diagnosis of mutation in 47 of 53 (87%) patients. For 6 patients, IHC was interpreted as wild-type while NGS indicated a mutation. NGS confirmed the IHC diagnosis of ATRX mutation in 29 of 31 (94%) patients. In 1 patient, IHC predicted a mutation that was not confirmed by NGS, and in another, IHC predicted wild-type, but NGS showed mutant. In 2 other patients, IHC diagnosis of ATRX mutation was equivocal; 1 was mutant and 1 was wild-type by NGS. Our single-center study suggests that IHC for IDH1/R132H, BRAF/V600E, and H3/K27M is highly reliable and may be used confidently in clinical practice. IHC for p53 and ATRX mutations is often reliable but possibly problematic, and genetic studies may be necessary to determine astrocytic or oligodendroglial differentiation.

Methylation of hypoxia-inducible factor (HIF)-1α by G9a/GLP inhibits HIF-1 transcriptional activity and cell migration.

Hypoxia-inducible factor 1 (HIF-1) is a master transcriptional regulator in response to hypoxia and its transcriptional activity is crucial for cancer cell mobility. Here we present evidence for a novel epigenetic mechanism that regulates HIF-1 transcriptional activity and HIF-1-dependent migration of glioblastoma cells. The lysine methyltransferases G9a and GLP directly bound to the α subunit of HIF-1 (HIF-1α) and catalyzed mono- and di-methylation of HIF-1α at lysine (K) 674 in vitro and in vivo. K674 methylation suppressed HIF-1 transcriptional activity and expression of its downstream target genes PTGS1, NDNF, SLC6A3, and Linc01132 in human glioblastoma U251MG cells. Inhibition of HIF-1 by K674 methylation is due to reduced HIF-1α transactivation domain function but not increased HIF-1α protein degradation or impaired binding of HIF-1 to hypoxia response elements. K674 methylation significantly decreased HIF-1-dependent migration of U251MG cells under hypoxia. Importantly, we found that G9a was downregulated by hypoxia in glioblastoma, which was inversely correlated with PTGS1 expression and survival of patients with glioblastoma. Therefore, our findings uncover a hypoxia-induced negative feedback mechanism that maintains high activity of HIF-1 and cell mobility in human glioblastoma.

BRAF mutation leading to central nervous system rosai-dorfman disease.

Rosai-Dorfman disease (RDD) is an uncommon histiocytic proliferative disorder that can present in nodal, extranodal, or, extremely rarely, in central nervous system (CNS)-restricted form. RDD is characterized histologically as a non-Langerhans cell histiocytosis composed of atypical CD68+ /S-100+ /CD1a- macrophages demonstrating prominent emperipolesis and effacement of the surrounding tissue. Previously thought to represent a reactive process, recent studies have raised the possibility that RDD and other histiocytic lesions, including Erdheim-Chester and Langerhans cell histiocytosis, are clonal processes linked to somatic mutations in the mitogen-activated protein (MAP) kinase pathway. Herein, we present a fatal case of RDD isolated to the CNS and used a next-generation targeted gene panel and Sanger sequencing to uncover a pathogenic deletion in the ß3-αC loop of the kinase domain in exon 12 of BRAF. This mutation, previously described in melanoma and Langerhans cell histiocytosis, represents the first BRAF mutation of this kind identified in RDD. These findings support the idea that RDD is a neoplastic condition and raise the possibility that inhibitors of the MAP kinase pathway may be effective in RDD. Ann Neurol 2018;83:147-152.

Rapid progression to glioblastoma in a subset of IDH-mutated astrocytomas: a genome-wide analysis.

According to the recently updated World Health Organization (WHO) classification (2016), grade II-III astrocytomas are divided into IDH-wildtype and IDH-mutant groups, the latter being significantly less aggressive in terms of both progression-free and total survival. We identified a small cohort of WHO grade II-III astrocytomas that harbored the IDH1 R132H mutation, as confirmed by both immunohistochemistry and molecular sequence analysis, which nonetheless had unexpectedly rapid recurrence and subsequent progression to glioblastoma. Among these four cases, the mean time to recurrence as glioblastoma was only 16 months and the mean total survival among the three patients who have died during the follow-up was only 31 months. We hypothesized that these tumors had other, unfavorable genetic or epigenetic alterations that negated the favorable effect of the IDH mutation. We applied genome-wide profiling with a methylation array (Illumina Infinium Human Methylation 450k) to screen for genetic and epigenetic alterations in these tumors. As expected, the methylation profiles of all four tumors were found to match most closely with IDH-mutant astrocytomas. Compared with a control group of four indolent, age-similar WHO grade II-III astrocytomas, the tumors showed markedly increased levels of overall copy number changes, but no consistent specific genetic alterations were seen across all of the tumors. While most IDH-mutant WHO grade II-III astrocytomas are relatively indolent, a subset may rapidly recur and progress to glioblastoma. The precise underlying cause of the increased aggressiveness in these gliomas remains unknown, although it may be associated with increased genomic instability.

Unusual skull tumors with psammomatoid bodies: a diagnostic challenge.

AIM: We describe a series of three diagnostically challenging, histologically similar fibro-osseous skull masses. METHODS: The cases were identified in our archives among 50,000 neuropathology specimens. A comprehensive review of the histological, immunohistochemical, ultrastructural, and imaging features as well as the clinical outcome was performed. RESULTS: The routine histology was similar in all 3 cases and showed spindle cell proliferations with frequent calcospheres or psammomatoid bodies. There was no evidence of an underlying subdural component. Immunohistochemistry for the meningioma markers EMA and SSTR2A raised the possibility of intraosseous meningioma, as all 3 lesions were convincingly positive for epithelial membrane antigen (EMA) and 1 lesion was convincingly positive for the somatostatin receptor subtype 2A (SSTR2A); weak, questionable positivity for SSTR2 was present in the remaining 2 cases. In addition, electron microscopy was available in 1 case and showed features consistent with meningioma. CONCLUSIONS: Overall, the findings were most consistent with intraosseous meningioma. Primary intraosseous meningiomas are rare lesions that may present a diagnostic challenge. It is important to consider meningiomas in the differential diagnosis, as extradural meningiomas are associated with an increased risk of recurrence and may occasionally undergo malignant transformation.
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Epidural spinal cavernous hemangioma and hybrid vascular subtype.

AIM: To demonstrate less common pathologies of purely epidural spinal tumors that should be considered when noted on MRI prior to surgery. To expand the differential diagnosis of purely epidural spinal tumors and comment on their surgical implications. MATERIAL AND METHODS: We report on two patients from our institution with rare pathology. We also utilized PubMed to concisely review the literature concerning purely epidural vascular lesions akin to the cavernous hemangioma. RESULTS: We describe common clinical presentations, radiographic findings, histopathologic characteristics and treatment algorithms relevant to the rare pure spinal epidural cavernous hemangioma and a newly described compound hemangioma subtype. CONCLUSION: Epidural spinal tumors are relatively common entities, though lesions isolated to the epidural space without origination in the vertebral body or as part of neurologic presentation of metastatic disease, are much less common. Less common pathologies may be missed in the initial differential diagnosis with treatment implications at surgery.

High expression of the stem cell marker nestin is an adverse prognostic factor in WHO grade II-III astrocytomas and oligoastrocytomas.

Infiltrating astrocytomas and oligoastrocytomas of low to anaplastic grade (WHO grades II and III), in spite of being associated with a wide range of clinical outcomes, can be difficult to subclassify and grade by the current histopathologic criteria. Unlike oligodendrogliomas and anaplastic oligodendrogliomas that can be identified by the 1p/19q codeletion and the more malignant glioblastomas (WHO grade IV astrocytomas) that can be diagnosed solely based on objective features on routine hematoxylin and eosin sections, no such objective criteria exist for the subclassification of grade II-III astrocytomas and oligoastrocytomas (A+OA II-III). In this study, we evaluated the prognostic and predictive value of the stem cell marker nestin in adult A+OA II-III (n = 50) using immunohistochemistry and computer-assisted analysis on tissue microarrays. In addition, the correlation between nestin mRNA level and total survival was analyzed in the NCI Rembrandt database. The results showed that high nestin expression is a strong adverse prognostic factor for total survival (p = 0.0004). The strength of the correlation was comparable to but independent of the isocitrate dehydrogenase 1/2 (IDH 1/2) mutation status. Histopathological grading and subclassification did not correlate significantly with outcome, although the interpretation of this finding is limited by the fact that grade III tumors were treated more aggressively than grade II tumors. These results suggest that nestin level and IDH 1/2 mutation status are strong prognostic features in A+OA II-III and possibly more helpful for treatment planning than routine histopathological variables such as oligodendroglial component (astrocytoma vs. oligoastrocytoma) and WHO grade (grade II vs. III).

Functional müllerian tissue within the conus medullaris generating cyclical neurological morbidity in an otherwise healthy female.

PURPOSE: Endometriosis is a common disease; however, ectopic müllerian tissue within the spine is a rare entity with the potential for producing significant neurological compromise. There are several postulated etiologies for this phenomenon, and only a few case reports are available in the world literature. Knowledge of this rare phenomenon is of paramount importance, since early diagnosis can lead to lessened neurological morbidity. METHODS: In this manuscript, we present a case report, discuss gynecological and neurosurgical perspectives relating to the treatment strategies for managing this entity, and propose an alternative explanation for such an occurrence from a neurogenetic standpoint. RESULTS: We present a case of spinal müllerianosis within the conus medullaris which was managed symptomatically for several years with an intracystic drain and subcutaneous reservoir. Over the years, it became clear that there was a cyclical presentation to her clinical malady, which at times was severe. Ultimately, she required surgical resection which aided in her diagnosis and subsequent treatment. CONCLUSION: Intraspinal müllerianosis is a rare location for an otherwise common disease in women and has the potential to create significant neurological morbidity by creating a mass lesion. Although the exact etiology remains unclear, the histogenic theories of embryologic origin appear most plausible. Treatment strategies for this condition may include hormonal therapy, obstetrical surgery, or open spinal surgery. This unusual and poorly understood disease should be considered in the differential diagnosis for intraspinal lesions presenting with hemorrhage in the clinical context of cyclical neurological symptoms.

Metabolism of [U-13 C]glucose in human brain tumors in vivo.

Glioblastomas and brain metastases demonstrate avid uptake of 2-[(18) F]fluoro-2-deoxyglucose by positron emission tomography and display perturbations of intracellular metabolite pools by (1) H MRS. These observations suggest that metabolic reprogramming contributes to brain tumor growth in vivo. The Warburg effect, excess metabolism of glucose to lactate in the presence of oxygen, is a hallmark of cancer cells in culture. 2-[(18) F]Fluoro-2-deoxyglucose-positive tumors are assumed to metabolize glucose in a similar manner, with high rates of lactate formation relative to mitochondrial glucose oxidation, but few studies have specifically examined the metabolic fates of glucose in vivo. In particular, the capacity of human brain cancers to oxidize glucose in the tricarboxylic acid cycle is unknown. Here, we studied the metabolism of human brain tumors in situ. [U-(13) C]Glucose (uniformly labeled glucose, i.e. d-glucose labeled with (13) C in all six carbons) was infused during surgical resection, and tumor samples were subsequently subjected to (13) C NMR spectroscopy. The analysis of tumor metabolites revealed lactate production, as expected. We also determined that pyruvate dehydrogenase, turnover of the tricarboxylic acid cycle, anaplerosis and de novo glutamine and glycine synthesis contributed significantly to the ultimate disposition of glucose carbon. Surprisingly, less than 50% of the acetyl-coenzyme A pool was derived from blood-borne glucose, suggesting that additional substrates contribute to tumor bioenergetics. This study illustrates a convenient approach that capitalizes on the high information content of (13) C NMR spectroscopy and enables the analysis of intermediary metabolism in diverse cancers growing in their native microenvironment.

Glucose metabolism via the pentose phosphate pathway, glycolysis and Krebs cycle in an orthotopic mouse model of human brain tumors.

It has been hypothesized that increased flux through the pentose phosphate pathway (PPP) is required to support the metabolic demands of rapid malignant cell growth. Using orthotopic mouse models of human glioblastoma (GBM) and renal cell carcinoma metastatic to brain, we estimated the activity of the PPP relative to glycolysis by infusing [1,2-(13) C(2) ]glucose. The [3-(13) C]lactate/[2,3-(13) C(2) ]lactate ratio was similar for both the GBM and brain metastasis and their respective surrounding brains (GBM, 0.197 ± 0.011 and 0.195 ± 0.033, respectively (p = 1); metastasis: 0.126 and 0.119 ± 0.033, respectively). This suggests that the rate of glycolysis is significantly greater than the PPP flux in these tumors, and that the PPP flux into the lactate pool is similar in both tumors. Remarkably, (13) C-(13) C coupling was observed in molecules derived from Krebs cycle intermediates in both tumor types, denoting glucose oxidation. In the renal cell carcinoma, in contrast with GBM, (13) C multiplets of γ-aminobutyric acid (GABA) differed from its precursor glutamate, suggesting that GABA did not derive from a common glutamate precursor pool. In addition, the orthotopic renal tumor, the patient's primary renal mass and brain metastasis were all strongly immunopositive for the 67-kDa isoform of glutamate decarboxylase, as were 84% of tumors on a renal cell carcinoma tissue microarray of the same histology, suggesting that GABA synthesis is cell autonomous in at least a subset of renal cell carcinomas. Taken together, these data demonstrate that (13) C-labeled glucose can be used in orthotopic mouse models to study tumor metabolism in vivo and to ascertain new metabolic targets for cancer diagnosis and therapy.

Surgical Management of a Massive Frontal Bone Hemangioma: Case Report.

Intraosseous hemangiomas are rare, benign tumors that can arise from the calvarium. These lesions often invade the outer table of the skull, but typically spare the inner table and intracranial structures. En bloc surgical resection is the standard treatment for intraosseous hemangiomas. However, a piecemeal resection may be required to safely remove the tumor in cases involving the inner table to protect the underlying brain parenchyma and vascular structures. Proper reconstruction is critical to optimize the cosmetic outcome, and a staged procedure allowing implantation of a custom-made implant can be considered for large lesions involving the forehead. We present a case of a patient with a large frontal intraosseous hemangioma with intradural involvement to highlight the surgical nuances of resection and review the existing literature regarding optimal management of these patients.

Epigenetic and genomic profiling of chordoid meningioma: implications for clinical management.

Chordoid meningioma is a morphological variant of meningioma designated as WHO grade 2. However, the recurrence rates varied widely in different case series, and to date, a unifying molecular genetic signature has not been identified. Among 1897 meningiomas resected at our institution, we identified 12 primary chordoid meningiomas from 12 patients. Histologically, all 12 cases had predominant (> 50%) chordoid morphology. Ten were otherwise grade 1, and two were also atypical. We performed DNA global methylation profile, copy number variation analysis, and targeted next-generation sequencing on 11 chordoid meningiomas, and compared to those of 51 non-chordoid, mostly high grade meningiomas. The chordoid meningiomas demonstrated a unique methylation profile in tSNE, UMAP, and hierarchical heatmap clustering analyses of the most differentially methylated CpGs. The most common copy number variation in chordoid meningioma was loss of 1p (7/11, 64%). Three chordoid meningiomas had 2p loss, which was significantly higher than the non-chordoid control cohort (27% vs 7.2%, p = 0.035). 22q loss was only seen in the two cases with additional atypical histological features. Chordoid meningiomas were enriched in mutations in chromatin remodeling genes EP400 (8/11,73%) KMT2C (4/11, 36%) and KMT2D (4/11, 36%), and showed low or absent NF2, TERT, SMO, and AKT1 mutations. Prognosis wise, only one case recurred. This case had atypical histology and high-grade molecular features including truncating NF2 mutation, 1p, 8p, 10, 14, 22q loss, and homozygous deletion of CDKN2A/B. Progression free survival of chordoid, otherwise grade 1 meningioma was comparable to non-chordoid WHO grade 1 meningioma (p = 0.75), and significantly better than chordoid WHO grade 2 meningioma (p = 0.019). Conclusion: the chordoid histology alone may not justify a universal WHO grade 2 designation. Screening for additional atypical histological or molecular genetic features is recommended.

Distant Pituitary Adenoma Spread: A Systematic Review and Report of 2 Cases.

BACKGROUND: Distant spread of pituitary adenoma outside the sellar/suprasellar region is classified as pituitary carcinoma. Cerebrospinal fluid (CSF)-born spread of pituitary adenoma can occur after tumor cell spillage into the CSF space after surgery, irradiation, or apoplexy and is not necessarily related to intrinsic tumor biology. OBJECTIVE: To systematically review the literature and describe the clinical characteristics and treatment strategies of patients with pituitary carcinomas. We further present 2 cases from our institution. METHODS: A single-center retrospective review of patients with pituitary adenoma spread to distant intracranial locations between 2000 and 2020 was performed. Electronic databases were searched from their inception to May 25, 2021, and studies describing patients with pituitary spread to distant locations were included. RESULTS: Of 1210 pituitary adenoma cases reviewed, 2 (0.16%) showed tumor spread to distant locations. We found 134 additional cases (from 108 published articles) resulting in a total of 136 cases (61.9% were male). The time to tumor spread ranged between 0 and 516 months (median: 96 months). The follow-up duration ranged between 0 and 240 months (median: 11.5 months). All but 2 patients (98.5%) underwent surgical resection before adenoma spread. The 2 exceptions included a patient with evidence of an apoplectic event on autopsy and another patient with leptomeningeal pituitary spread but an unclear history of apoplexy. Elevated tumor markers were not linked to poor outcomes. CONCLUSION: Distant spread of pituitary adenoma may occur after surgery, irradiation, or apoplexy. It is not necessarily associated with a malignant clinical course.

Alterations in the RB Pathway With Inactivation of RB1 Characterize Glioblastomas With a Primitive Neuronal Component.

A primitive neuronal component is a feature of some glioblastomas but defining molecular alterations of this histologic variant remains uncertain. We performed next-generation sequencing of 1500 tumor related genes on tissue from 9 patients with glioblastoma with a primitive component (G/PN) and analyzed 27 similar cases from the Cancer Genome Atlas (TCGA) dataset. Alterations in the RB pathway were identified in all of our patients' tumors and 81% of TCGA tumors with the retinoblastoma tumor suppressor gene (RB1) commonly affected. Although RB1 mutations were observed in some conventional glioblastomas, the allelic fractions of these mutations were significantly higher in tumors with a primitive neuronal component in both our and TCGA cohorts (median, 72% vs 25%, p < 0.001 and 80% vs 40%, p < 0.02, respectively). Further, in 78% of patients in our cohort, RB expression was lost by immunohistochemistry. Our findings indicate that alterations in the RB pathway are common in G/PNs and suggest that inactivation of RB1 may be a driving mechanism for the phenotype.

Lymphomatoid granulomatosis of the central nervous system (CNS-LYG) posing a management challenge.

Isolated central nervous system lymphomatoid granulomatosis (CNS-LYG) can mimic aggressive glioblastomas. We describe a complex presentation of CNS-LYG coexisting with immune thrombocytopenia successfully managed with rituximab and ultra-low-dose radiation therapy.

Mutation Status and Epithelial Differentiation Stratify Recurrence Risk in Chordoid Meningioma-A Multicenter Study with High Prognostic Relevance.

Chordoid meningioma is a rare WHO grade II histologic variant. Its molecular alterations or their impact on patient risk stratification have not been fully explored. We performed a multicenter, clinical, histological, and genomic analysis of chordoid meningiomas from 30 patients (34 tumors), representing the largest integrated study to date. By NHERF1 microlumen immunohistochemical detection, three epithelial differentiation (ED) groups emerged: #1/fibroblastic-like, #2/epithelial-poorly-differentiated and #3/epithelial-well-differentiated. These ED groups correlated with tumor location and genetic profiling, with NF2 and chromatin remodeling gene mutations clustering in ED group #2, and TRAF7 mutations segregating in ED group #3. Mutations in LRP1B were found in the largest number of cases (36%) across ED groups #2 and #3. Pathogenic ATM and VHL germline mutations occurred in ED group #3 patients, conferring an aggressive or benign course, respectively. The recurrence rate significantly correlated with mutations in NF2, as single gene, and with mutations in chromatin remodeling and DNA damage response genes, as groups. The recurrence rate was very high in ED group #2, moderate in ED group #3, and absent in ED group #1. This study proposes guidelines for tumor recurrence risk stratification and practical considerations for patient management.

Extraneural metastatic anaplastic ependymoma: a systematic review and a report of metastases to bilateral parotid glands.

BACKGROUND: Anaplastic ependymoma with extraneural metastases is associated with a poor clinical outcome. Metastatic spread to the parotid gland is a rare clinical entity that requires multidisciplinary intervention. Herein, we present a systematic review of anaplastic ependymoma with extraneural metastases and report on a case with metastases to both parotid glands. METHODS: Electronic databases were searched from their inception to February 2019. Inclusion criteria included reports of anaplastic ependymoma with extraneural metastasis. Studies were excluded if the tumor grade was not reported. A case illustration is provided. RESULTS: The search yielded 15 cases of anaplastic ependymoma with extraneural metastases, including the present case. Mean age at diagnosis was 15 years. The initial tumor location was predominantly supratentorial (93.3%). All cases demonstrated leptomeningeal seeding before extraneural metastasis. Mean survival from initial diagnosis was 4.5 years. Metastasis to the parotid gland occurred in 2 cases, including the present case. We present a 17-year-old female patient who underwent gross total resection of a supratentorial, paraventricular anaplastic ependymoma followed by adjuvant external beam radiation therapy. The patient developed recurrent leptomeningeal seeding, treated with Gamma Knife radiosurgery over a 5-year period. She returned with a parotid mass and cervical lymphadenopathy and underwent parotidectomy and modified radical neck dissection. She continued to experience recurrences, including the left parotid gland, and was ultimately placed in hospice care. CONCLUSIONS: Anaplastic ependymoma with extraneural metastasis is rare. A combination of repeated surgical resection, radiation therapy, and chemotherapy can be used to manage recurrent and metastatic disease, but outcomes remain poor.

Glycine by MR spectroscopy is an imaging biomarker of glioma aggressiveness.

BACKGROUND: High-grade gliomas likely remodel the metabolic machinery to meet the increased demands for amino acids and nucleotides during rapid cell proliferation. Glycine, a non-essential amino acid and intermediate of nucleotide biosynthesis, may increase with proliferation. Non-invasive measurement of glycine by magnetic resonance spectroscopy (MRS) was evaluated as an imaging biomarker for assessment of tumor aggressiveness. METHODS: We measured glycine, 2-hydroxyglutarate (2HG), and other tumor-related metabolites in 35 glioma patients using an MRS sequence tailored for co-detection of glycine and 2HG in gadolinium-enhancing and non-enhancing tumor regions on 3T MRI. Glycine and 2HG concentrations as measured by MRS were correlated with tumor cell proliferation (MIB-1 labeling index), expression of mitochondrial serine hydroxymethyltransferase (SHMT2), and glycine decarboxylase (GLDC) enzymes, and patient overall survival. RESULTS: Elevated glycine was strongly associated with presence of gadolinium enhancement, indicating more rapidly proliferative disease. Glycine concentration was positively correlated with MIB-1, and levels higher than 2.5 mM showed significant association with shorter patient survival, irrespective of isocitrate dehydrogenase status. Concentration of 2HG did not correlate with MIB-1 index. A high glycine/2HG concentration ratio, >2.5, was strongly associated with shorter survival (P < 0.0001). GLDC and SHMT2 expression were detectable in all tumors with glycine concentration, demonstrating an inverse correlation with GLDC. CONCLUSIONS: The data suggest that aggressive gliomas reprogram glycine-mediated one-carbon metabolism to meet the biosynthetic demands for rapid cell proliferation. MRS evaluation of glycine provides a non-invasive metabolic imaging biomarker that is predictive of tumor progression and clinical outcome. KEY POINTS: 1. Glycine and 2-hydroxyglutarate in glioma patients are precisely co-detected using MRS at 3T.2. Tumors with elevated glycine proliferate and progress rapidly.3. A high glycine/2HG ratio is predictive of shortened patient survival.

Neuroanatomic profile of polyglutamine immunoreactivity in Huntington disease brains.

A pathologic hallmark of Huntington disease (HD) is the presence of intraneuronal aggregates of polyglutamine-containing huntingtin protein fragments. Monoclonal antibody 1C2 is a commercial antibody to normal human TATA-binding protein that detects long stretches of glutamine residues. Using 1C2 as a surrogate marker formutant huntingtin protein, we immunostained 19 HD cases, 10 normal controls, and 10 cases of frontotemporal degeneration with ubiquitinated inclusions as diseased controls. In the HD cases, there was consistent 1C2 immunoreactivity in the neocortex, striatum, hippocampus, lateral geniculate body, basis pontis, medullary reticular formation, and cerebellar dentate nucleus. The normal and diseased controls demonstrated 1C2 immunoreactivity only in the substantia nigra, locus coeruleus, and pituitary gland. Staining of 5 HD cases and 5 normal controls revealed a less consistent and less diagnostically useful morphologic immunoreactivity profile. These results indicate that widespread 1C2 immunoreactivity is present in diverse central nervous system areas in HD, and that in the appropriate setting, 1C2 staining can be a useful tool in the postmortem diagnosis of HD when neuromelanin-containing neuronal populations are avoided.