Inhibitory CD161 receptor identified in glioma-infiltrating T cells by single-cell analysis.

T cells are critical effectors of cancer immunotherapies, but little is known about their gene expression programs in diffuse gliomas. Here, we leverage single-cell RNA sequencing (RNA-seq) to chart the gene expression and clonal landscape of tumor-infiltrating T cells across 31 patients with isocitrate dehydrogenase (IDH) wild-type glioblastoma and IDH mutant glioma. We identify potential effectors of anti-tumor immunity in subsets of T cells that co-express cytotoxic programs and several natural killer (NK) cell genes. Analysis of clonally expanded tumor-infiltrating T cells further identifies the NK gene KLRB1 (encoding CD161) as a candidate inhibitory receptor. Accordingly, genetic inactivation of KLRB1 or antibody-mediated CD161 blockade enhances T cell-mediated killing of glioma cells in vitro and their anti-tumor function in vivo. KLRB1 and its associated transcriptional program are also expressed by substantial T cell populations in other human cancers. Our work provides an atlas of T cells in gliomas and highlights CD161 and other NK cell receptors as immunotherapy targets.

Reconstructing and reprogramming the tumor-propagating potential of glioblastoma stem-like cells.

Developmental fate decisions are dictated by master transcription factors (TFs) that interact with cis-regulatory elements to direct transcriptional programs. Certain malignant tumors may also depend on cellular hierarchies reminiscent of normal development but superimposed on underlying genetic aberrations. In glioblastoma (GBM), a subset of stem-like tumor-propagating cells (TPCs) appears to drive tumor progression and underlie therapeutic resistance yet remain poorly understood. Here, we identify a core set of neurodevelopmental TFs (POU3F2, SOX2, SALL2, and OLIG2) essential for GBM propagation. These TFs coordinately bind and activate TPC-specific regulatory elements and are sufficient to fully reprogram differentiated GBM cells to "induced" TPCs, recapitulating the epigenetic landscape and phenotype of native TPCs. We reconstruct a network model that highlights critical interactions and identifies candidate therapeutic targets for eliminating TPCs. Our study establishes the epigenetic basis of a developmental hierarchy in GBM, provides detailed insight into underlying gene regulatory programs, and suggests attendant therapeutic strategies. PAPERCLIP:

Atretic cephalocele and encephalocele: A single-institution clinicopathological study.

BACKGROUND: Encephaloceles are neural tube defects characterized by herniation of meninges, neural tissue and cerebrospinal fluid, while atretic cephaloceles denote a rudimentary connection to the intracranial space with absence of herniated neural tissue and represent an infrequent dermatopathologic diagnosis. Limited reports of these entities confound the challenge in their histopathologic distinction. Accurate classification is important given associated anomalies and neurologic manifestations that impact prognosis. METHODS: We describe the clinicopathological and immunohistochemical [glial fibrillary acidic protein (GFAP), S100, epithelial membrane antigen (EMA), and somatostatin receptor subtype 2A (SSTR2A)] features in a retrospective series encountered at a single institution between 1994 and 2020. RESULTS: We identified 13 cases classified as atretic cephalocele (n = 11) and encephalocele (n = 2). Hamartomatous changes and multinucleated cells were unique to atretic cephaloceles while myxoid areas were unique to encephaloceles. At least focal staining for SSTRA was seen in all atretic cephaloceles with the majority (87.5%) staining for EMA; negative staining for GFAP and S100 confirmed absence of neural tissue. Encephaloceles were GFAP and S100 positive, and negative for SSTR2 and EMA. Atretic cephaloceles had a favorable prognosis compared to encephaloceles, with severe morbidity present in both encephalocele cases. CONCLUSION: Our study raises awareness of atretic cephalocele and encephalocele among dermatopathologists and reveals a mutually exclusive immunophenotype that facilitates their distinction for prognostication and management.

Single-cell RNA-seq supports a developmental hierarchy in human oligodendroglioma.

Although human tumours are shaped by the genetic evolution of cancer cells, evidence also suggests that they display hierarchies related to developmental pathways and epigenetic programs in which cancer stem cells (CSCs) can drive tumour growth and give rise to differentiated progeny. Yet, unbiased evidence for CSCs in solid human malignancies remains elusive. Here we profile 4,347 single cells from six IDH1 or IDH2 mutant human oligodendrogliomas by RNA sequencing (RNA-seq) and reconstruct their developmental programs from genome-wide expression signatures. We infer that most cancer cells are differentiated along two specialized glial programs, whereas a rare subpopulation of cells is undifferentiated and associated with a neural stem cell expression program. Cells with expression signatures for proliferation are highly enriched in this rare subpopulation, consistent with a model in which CSCs are primarily responsible for fuelling the growth of oligodendroglioma in humans. Analysis of copy number variation (CNV) shows that distinct CNV sub-clones within tumours display similar cellular hierarchies, suggesting that the architecture of oligodendroglioma is primarily dictated by developmental programs. Subclonal point mutation analysis supports a similar model, although a full phylogenetic tree would be required to definitively determine the effect of genetic evolution on the inferred hierarchies. Our single-cell analyses provide insight into the cellular architecture of oligodendrogliomas at single-cell resolution and support the cancer stem cell model, with substantial implications for disease management.

Clinical sensitivity and interpretation of PCR and serological COVID-19 diagnostics for patients presenting to the hospital.

The diagnosis of COVID-19 requires integration of clinical and laboratory data. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostic assays play a central role in diagnosis and have fixed technical performance metrics. Interpretation becomes challenging because the clinical sensitivity changes as the virus clears and the immune response emerges. Our goal was to examine the clinical sensitivity of two most common SARS-CoV-2 diagnostic test modalities, polymerase chain reaction (PCR) and serology, over the disease course to provide insight into their clinical interpretation in patients presenting to the hospital. We conducted a single-center, retrospective study. To derive clinical sensitivity of PCR, we identified 209 PCR-positive SARS-CoV-2 patients with multiple PCR test results (624 total PCR tests) and calculated daily sensitivity from date of symptom onset or first positive test. Clinical sensitivity of PCR decreased with days post symptom onset with >90% clinical sensitivity during the first 5 days after symptom onset, 70%-71% from Days 9 to 11, and 30% at Day 21. To calculate daily clinical sensitivity by serology, we utilized 157 PCR-positive patients with a total of 197 specimens tested by enzyme-linked immunosorbent assay for IgM, IgG, and IgA anti-SARS-CoV-2 antibodies. In contrast to PCR, serological sensitivity increased with days post symptom onset with >50% of patients seropositive by at least one antibody isotype after Day 7, >80% after Day 12, and 100% by Day 21. Taken together, PCR and serology are complimentary modalities that require time-dependent interpretation. Superimposition of sensitivities over time indicate that serology can function as a reliable diagnostic aid indicating recent or prior infection.

High Seroprevalence of Anti-SARS-CoV-2 Antibodies in Chelsea, Massachusetts.

SARS-CoV-2 antibody testing allows quantitative determination of disease prevalence, which is especially important in high-risk communities. We performed anonymized convenience sampling of 200 currently asymptomatic residents of Chelsea, the epicenter of COVID-19 illness in Massachusetts, by BioMedomics SARS-CoV-2 combined IgM-IgG point-of-care lateral flow immunoassay. The seroprevalence was 31.5% (17.5% IgM+IgG+, 9.0% IgM+IgG-, and 5.0% IgM-IgG+). Of the 200 participants, 50.5% reported no symptoms in the preceding 4 weeks, of which 24.8% (25/101) were seropositive, and 60% of these were IgM+IgG-. These data are the highest seroprevalence rates observed to date and highlight the significant burden of asymptomatic infection.

The impact of histopathology and NAB2-STAT6 fusion subtype in classification and grading of meningeal solitary fibrous tumor/hemangiopericytoma.

Meningeal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is a rare tumor with propensity for recurrence and metastasis. Although multiple classification schemes have been proposed, optimal risk stratification remains unclear, and the prognostic impact of fusion status is uncertain. We compared the 2016 WHO CNS tumor grading scheme (CNS-G), a three-tier system based on histopathologic phenotype and mitotic count, to the 2013 WHO soft-tissue counterpart (ST-G), a two-tier system based on mitotic count alone, in a cohort of 133 patients [59 female, 74 male; mean age 54 years (range 20-87)] with meningeal SFT/HPC. Tumors were pathologically confirmed through review of the first tumor resection (n = 97), local recurrence (n = 35), or distant metastasis (n = 1). A STAT6 immunostain showed nuclear expression in 132 cases. NAB2-STAT6 fusion was detected in 99 of 111 successfully tested tumors (89%) including the single STAT6 immunonegative tumor. Tumors were classified by CNS-G as grade 1 (n = 43), 2 (n = 41), or 3 (n = 49), and by ST-G as SFT (n = 84) or malignant SFT (n = 49). Necrosis was present in 16 cases (12%). On follow-up, 42 patients had at least one subsequent recurrence or metastasis (7 metastasis only, 33 recurrence only, 2 patients had both). Twenty-nine patients died. On univariate analysis, necrosis (p = 0.002), CNS-G (p = 0.01), and ST-G (p = 0.004) were associated with recurrence-free (RFS) but not overall survival (OS). NAB2-STAT6 fusion type was not significantly associated with RFS or OS, but was associated with phenotype. A modified ST-G incorporating necrosis showed higher correlation with RFS (p = 0.0006) and remained significant (p = 0.02) when considering only the primary tumors. From our data, mitotic rate and necrosis appear to stratify this family of tumors most accurately and could be incorporated in a future grading scheme.

Characterization of applicants for residency training in pathology: Does diversity exist?

CONTEXT: A diverse workforce has been shown to improve productivity and innovation. The level of diversity among pathology residency applicants has not previously been reported. OBJECTIVE: This study aims to characterize the applicants at an academic pathology department to gain a better understanding of diversity among them. DESIGN: Between 2015 and 2017, data from a tertiary care center were analyzed for gender, US and international medical school, USMLE scores, and self-identified racial or ethnic group. For 2017, data was compared to that published by the Association of American Medical Colleges (AAMC). RESULTS: There were 1293 pathology applicants with 48-49% being female. The overall underrepresented minority (URM) applicant pool in pathology represented 12.6%, 9.5%, and 11.1% of our applicants for 2015, 2016, and 2017, respectively. URMs from US medical schools alone represented 4.7%, 3.7%, and 4.5% of our applicants for 2015, 2016, and 2017, respectively. The percentage of 2017 US medical school graduates applying to any US pathology training program was 22.2% versus 38.7% applying to pathology at our center (p ≤0.001). URM applicants for pathology from US medical schools were significantly lower than URM applicants to all AAMC medical specialties (p = 0.035). Among our pathology applicants in 2017, USMLE I scores and number of applicants with any publications were higher for non-URMs compared to URMs (p = 0.048 and p = 0.046, respectively). CONCLUSION: No significant difference related to gender was identified among our applicants while racial/ethnic groups remain underrepresented with significantly fewer URM applicants from US medical schools compared to published AAMC data for all medical specialties.

Novel, improved grading system(s) for IDH-mutant astrocytic gliomas.

According to the 2016 World Health Organization Classification of Tumors of the Central Nervous System (2016 CNS WHO), IDH-mutant astrocytic gliomas comprised WHO grade II diffuse astrocytoma, IDH-mutant (AIIIDHmut), WHO grade III anaplastic astrocytoma, IDH-mutant (AAIIIIDHmut), and WHO grade IV glioblastoma, IDH-mutant (GBMIDHmut). Notably, IDH gene status has been made the major criterion for classification while the manner of grading has remained unchanged: it is based on histological criteria that arose from studies which antedated knowledge of the importance of IDH status in diffuse astrocytic tumor prognostic assessment. Several studies have now demonstrated that the anticipated differences in survival between the newly defined AIIIDHmut and AAIIIIDHmut have lost their significance. In contrast, GBMIDHmut still exhibits a significantly worse outcome than its lower grade IDH-mutant counterparts. To address the problem of establishing prognostically significant grading for IDH-mutant astrocytic gliomas in the IDH era, we undertook a comprehensive study that included assessment of histological and genetic approaches to prognosis in these tumors. A discovery cohort of 211 IDH-mutant astrocytic gliomas with an extended observation was subjected to histological review, image analysis, and DNA methylation studies. Tumor group-specific methylation profiles and copy number variation (CNV) profiles were established for all gliomas. Algorithms for automated CNV analysis were developed. All tumors exhibiting 1p/19q codeletion were excluded from the series. We developed algorithms for grading, based on molecular, morphological and clinical data. Performance of these algorithms was compared with that of WHO grading. Three independent cohorts of 108, 154 and 224 IDH-mutant astrocytic gliomas were used to validate this approach. In the discovery cohort several molecular and clinical parameters were of prognostic relevance. Most relevant for overall survival (OS) was CDKN2A/B homozygous deletion. Other parameters with major influence were necrosis and the total number of CNV. Proliferation as assessed by mitotic count, which is a key parameter in 2016 CNS WHO grading, was of only minor influence. Employing the parameters most relevant for OS in our discovery set, we developed two models for grading these tumors. These models performed significantly better than WHO grading in both the discovery and the validation sets. Our novel algorithms for grading IDH-mutant astrocytic gliomas overcome the challenges caused by introduction of IDH status into the WHO classification of diffuse astrocytic tumors. We propose that these revised approaches be used for grading of these tumors and incorporated into future WHO criteria.

Grading of Diffuse Astrocytic Gliomas: A Review of Studies Before and After the Advent of IDH Testing.

Estimating the malignancy level of tumors is key to management, and has been part of oncology practice for the past ∼100 years. A central aspect of assessing malignancy level is based on histological "grading"-a process in which a pathologist evaluates microscopic features of a tumor and interprets those findings in light of large prognostic studies. For the diffuse astrocytic gliomas, there have been many such studies over the past century and these have proven useful in estimating prognosis for patients. With the advent of molecular genetics, molecular diagnostic testing has been added to histological evaluation in the armamentarium of the pathologist, and the recent World Health Organization (WHO) Classification of Tumors of the Central Nervous System encourages testing for isocitrate dehydrogenase (IDH) gene status in the classification of diffuse astrocytic gliomas. The present review catalogues a large series of diffuse astrocytic glioma grading studies over the past few decades, and compares the prognostic value of such grading schema before and after the emergence of IDH testing. The review concludes that novel approaches to diffuse astrocytic tumor grading are required in the era of IDH testing.

Localized crystal-storing histiocytosis of the posterior fossa.

Crystal-storing histiocytosis (CSH) is an uncommon histiocytic proliferation reported to involve diverse organs and tissues, but involvement of the central nervous system (CNS) is rare. In most cases CSH is identified in association with underlying lymphoproliferative, plasma cell diseases or rarely with various inflammatory or infectious conditions. CSH is characterized by the cytoplasmic accumulation of crystalline material in histiocytes, most commonly of kappa immunoglobulin light chain. We report a unique case of localized CSH involving the left cerebellum and caudal brain stem in a young man with a history of gout but without known lymphoproliferative or plasma cell disorders. Awareness of this entity is important diagnostically, but also to ensure appropriate management and follow-up, particularly in the absence of apparent underlying malignancy.

The 2016 WHO classification of central nervous system tumors: what neurologists need to know.

PURPOSE OF REVIEW: The 2016 WHO classification of tumors of the central nervous system (2016 CNS WHO) features many changes that are relevant to neurologists treating patients with brain tumors as well as neurologists involved in basic, clinical, and epidemiological research. This review summarizes what neurologists need to know and will need to know in the next years. RECENT FINDINGS: The 2016 CNS WHO introduces diagnostic terms that 'integrate' histological and molecular information and suggests presenting diagnoses in a four-layered reporting format. In addition, it utilizes a 'not otherwise specified' designation to identify diagnostic categories that are not precisely defined. A better understanding of the biology of entities further led to changes in the tumor nosology, for example, diffuse gliomas based on IDH gene status. Meaningful molecular subgroups could also be identified in embryonal tumors and other entities. Given the pace of change in the field of brain tumor classification, there will likely be additional practical advances that emerge over the next few years. A new initiative entitled Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy intends to formulate recommendations between WHO updates. SUMMARY: The 2016 CNS WHO includes major changes in the way brain tumors are classified, with molecular parameters being incorporated into diagnostic criteria for a substantial number of such entities.

The flowering of pathology as a medical discipline in Boston, 1892-c.1950: W.T. Councilman, FB Mallory, JH Wright, SB Wolbach and their descendants.

During most of the nineteenth century, the discipline of pathology in Boston made substantial strides as a result of physicians and surgeons who practiced pathology on a part-time basis. The present essay tells the subsequent story, beginning in 1892, when full-time pathologists begin to staff the medical schools and hospitals of Boston. Three individuals from this era deserve special mention: William T Councilman, Frank Burr Mallory and James Homer Wright, with Councilman remembered primarily as a visionary and teacher, Mallory as a trainer of many pathologists, and Wright as a scientist. Together with S Burt Wolbach in the early-to-mid-twentieth century, these pathologists went on to train the next generation of pathologists-a generation that then populated the various hospitals that were developed in Boston in the early 1900s. This group of seminal pathologists in turn formed the diagnostically strong, academically productive, pathology departments that grew in Boston over the remainder of the twentieth century.

The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary.

The 2016 World Health Organization Classification of Tumors of the Central Nervous System is both a conceptual and practical advance over its 2007 predecessor. For the first time, the WHO classification of CNS tumors uses molecular parameters in addition to histology to define many tumor entities, thus formulating a concept for how CNS tumor diagnoses should be structured in the molecular era. As such, the 2016 CNS WHO presents major restructuring of the diffuse gliomas, medulloblastomas and other embryonal tumors, and incorporates new entities that are defined by both histology and molecular features, including glioblastoma, IDH-wildtype and glioblastoma, IDH-mutant; diffuse midline glioma, H3 K27M-mutant; RELA fusion-positive ependymoma; medulloblastoma, WNT-activated and medulloblastoma, SHH-activated; and embryonal tumour with multilayered rosettes, C19MC-altered. The 2016 edition has added newly recognized neoplasms, and has deleted some entities, variants and patterns that no longer have diagnostic and/or biological relevance. Other notable changes include the addition of brain invasion as a criterion for atypical meningioma and the introduction of a soft tissue-type grading system for the now combined entity of solitary fibrous tumor / hemangiopericytoma-a departure from the manner by which other CNS tumors are graded. Overall, it is hoped that the 2016 CNS WHO will facilitate clinical, experimental and epidemiological studies that will lead to improvements in the lives of patients with brain tumors.

Completeness of required site-specific factors for brain and CNS tumors in the Surveillance, Epidemiology and End Results (SEER) 18 database (2004-2012, varying).

Cancer registries are an important source of population-level information on brain tumor incidence and survival. Surveillance, Epidemiology, and End Results (SEER) registries currently collect data on specific required factors related to brain tumors as defined by the American Joint Commission on Cancer, including World Health Organization (WHO) grade, MGMT methylation and 1p/19q codeletion status. We assessed 'completeness', defined as having valid values over the time periods that they have been collected, overall, by year, histology, and registry. Data were obtained through a SEER custom data request for four factors related to brain tumors for the years 2004-2012 (3/4 factors were collected only from 2010 to 2012). SEER*Stat was used to generate frequencies of 'completeness' for each factor overall, and by year, histology and registry. The four factors varied in completeness, but increased over time. WHO grade has been collected the longest, and showed significant increases in completeness. Completeness of MGMT and 1p/19q codeletion was highest for glioma subtypes for which testing is recommended by clinical practice guidelines. Completeness of all factors varied by histology and cancer registry. Overall, several of the factors had high completeness, and all increased in completeness over time. With increasing focus on 'precision medicine' and the incorporation of molecular parameters into the 2016 WHO CNS tumor classification, it is critical that the data are complete, and factors collected at the population level are fully integrated into cancer reporting. It is critical that cancer registries continue to collect established and emerging prognostic and predictive factors.

Evolutionary etiology of high-grade astrocytomas.

Glioblastoma (GBM), the most common brain malignancy, remains fatal with no effective treatment. Analyses of common aberrations in GBM suggest major regulatory pathways associated with disease etiology. However, 90% of GBMs are diagnosed at an advanced stage (primary GBMs), providing no access to early disease stages for assessing disease progression events. As such, both understanding of disease mechanisms and the development of biomarkers and therapeutics for effective disease management are limited. Here, we describe an adult-inducible astrocyte-specific system in genetically engineered mice that queries causation in disease evolution of regulatory networks perturbed in human GBM. Events yielding disease, both engineered and spontaneous, indicate ordered grade-specific perturbations that yield high-grade astrocytomas (anaplastic astrocytomas and GBMs). Impaired retinoblastoma protein RB tumor suppression yields grade II histopathology. Additional activation of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) network drives progression to grade III disease, and further inactivation of phosphatase and tensin homolog (PTEN) yields GBM. Spontaneous missense mutation of tumor suppressor Trp53 arises subsequent to KRAS activation, but before grade III progression. The stochastic appearance of mutations identical to those observed in humans, particularly the same spectrum of p53 amino acid changes, supports the validity of engineered lesions and the ensuing interpretations of etiology. Absence of isocitrate dehydrogenase 1 (IDH1) mutation, asymptomatic low grade disease, and rapid emergence of GBM combined with a mesenchymal transcriptome signature reflect characteristics of primary GBM and provide insight into causal relationships.

Cross-reactivity of the BRAF VE1 antibody with epitopes in axonemal dyneins leads to staining of cilia.

Antibodies that recognize neo-epitopes in tumor cells are valuable tools in the evaluation of tissue biopsy or resection specimens. The VE1 antibody that recognizes the V600E-mutant BRAF protein is one such example. We have recently shown that the vast majority of papillary craniopharyngiomas-tumors that arise in the sellar or suprasellar regions of the brain-harbor BRAF V600E mutations. The VE1 antibody can be effective in discriminating papillary craniopharyngioma from adamantinomatous craniopharyngioma, which harbors mutations in CTNNB1 and not BRAF. While further characterizing the use of the VE1 antibody in the differential diagnosis of suprasellar lesions, we found that the VE1 antibody stains the epithelial cells lining Rathke's cleft cysts with very strong staining of the cilia of these cells. We used targeted sequencing to show that Rathke's cleft cysts do not harbor the BRAF V600E mutation. Moreover, we found that the VE1 antibody reacts strongly with cilia in various structures-the bronchial airways, the fallopian tubes, the nasopharynx, and the epididymis-as well as with the flagella of sperm. In addition, VE1 reacts strongly with the cilia of the ependymal lining of the brain and with the cilia-containing microlumens of ependymoma tumors. There is significant sequence homology between the synthetic peptide (amino acid 596-606 of BRAF V600E: GLATEKSRWSG) that was used to generate the VE1 antibody and regions of multiple axonemal dynein heavy chain proteins (eg, DNAH2, DNAH7, and DNAH12). These proteins are major components of the axonemes of cilia and flagella where they drive the sliding of microtubules. In ELISA assays, we show that the VE1 antibody recognizes epitopes from these proteins. A familiarity with the cross-reactivity of the VE1 antibody with epitopes of proteins in cilia is of value when evaluating tissues stained with this important clinical antibody.

Completeness and concordancy of WHO grade assignment for brain and central nervous system tumors in the United States, 2004-2011.

Central nervous system (CNS) tumors are categorized and graded for clinical and research purposes according to the World Health Organization (WHO) scheme which segregates tumors by histological type and predicted biological behavior. However, reporting of WHO grade in pathological reports is inconsistent despite its collection in cancer registration. We studied the completeness, concordancy, and yearly trends in the collection of WHO grade for primary CNS tumors between 2004 and 2011. Data from the Surveillance, Epidemiology and End Results program were analyzed for the percentage of histologically diagnosed primary CNS tumor cases with concordantly documented WHO grades between 2004 and 2011. Yearly trends were calculated with annual percentage changes (APC) and 95% confidence intervals (95% CI). Completeness and concordancy of the collection of WHO grade varied significantly by histological type and year. The percentage of cases with documented WHO grade increased significantly from 2004 to 2011: 39.0% of cases in 2004 had documented WHO grade, while 77.5% of cases had documented grade in 2011 (APC, 10.3; 95% CI: 9.0, 11.5). Among cases with documented WHO grade, the percentage graded concordantly increased significantly from 89.1% in 2004 to 93.7% in 2007 (APC, 1.8; 95% CI: 1.0, 2.6) and these values varied over time by histological type. One common trend among all histologies was a significant increase in the percentage of cases with documented WHO grade. A sizeable proportion of reported CNS tumors collected by cancer registrars have undocumented WHO grade, while a much smaller proportion are graded discordantly. Data collection on grade has improved in completeness and concordancy over time. Efforts to further improve collection of this variable are essential for clinical care and the epidemiological surveillance of CNS tumors.