The role of clinical factors and immunocheckpoint molecules in the prognosis of patients with supratentorial extraventricular ependymoma: a single-center retrospective study.

PURPOSE: Supratentorial extraventricular ependymoma (SEE) is a rare subset of ependymomas located in the supratentorial parenchyma, and little is known regarding its management and prognosis. Our study aimed to reveal the prognostic factors in patients with SEE and the roles of programmed death ligand-1 (PD-L1), programmed cell death protein 1 (PD-1), Ki-67, and neural cell adhesion molecule L1 (L1CAM) in predicting these patients' outcomes. METHODS: We retrospectively studied the clinical features and prognostic factors in 48 patients with SEE admitted to our center from April 2008 to October 2018. Tissue slides were constructed from patient samples, and PD-L1, PD-1, Ki-67, and L1CAM expression levels were evaluated by immunohistochemistry. RESULTS: Patients with gross total resection (GTR) had better progression-free survival than patients with subtotal resection (STR). Moreover, the recurrence hazard ratios in patients with STR at 3, 5, and 10 years were 8.746, 6.866 and 3.962 times those of patients with GTR, respectively. PD-L1 positivity predicted worse progression-free survival, while the recurrence hazard ratios for patients with PD-L1 positivity at 3, 5, and 10 years were 10.445, 5.539, and 3.949 times those of patients with PD-L1 negativity, respectively. Multivariate analysis revealed that PD-L1 expression and GTR could independently predict outcomes in patients with SEE. CONCLUSION: PD-L1 expression was an independent and more readily obtained predictor of outcomes, representing a simple and reliable biological prognostic factor for patients with SEE. Further studies are needed to explore PD-L1 inhibitor treatment for patients with ependymoma. CLINICAL TRIAL REGISTRATION: No clinical trials were performed in the study.

Locoregional delivery of CAR T cells to the cerebrospinal fluid for treatment of metastatic medulloblastoma and ependymoma.

Recurrent medulloblastoma and ependymoma are universally lethal, with no approved targeted therapies and few candidates presently under clinical evaluation. Nearly all recurrent medulloblastomas and posterior fossa group A (PFA) ependymomas are located adjacent to and bathed by the cerebrospinal fluid, presenting an opportunity for locoregional therapy, bypassing the blood-brain barrier. We identify three cell-surface targets, EPHA2, HER2 and interleukin 13 receptor α2, expressed on medulloblastomas and ependymomas, but not expressed in the normal developing brain. We validate intrathecal delivery of EPHA2, HER2 and interleukin 13 receptor α2 chimeric antigen receptor T cells as an effective treatment for primary, metastatic and recurrent group 3 medulloblastoma and PFA ependymoma xenografts in mouse models. Finally, we demonstrate that administration of these chimeric antigen receptor T cells into the cerebrospinal fluid, alone or in combination with azacytidine, is a highly effective therapy for multiple metastatic mouse models of group 3 medulloblastoma and PFA ependymoma, thereby providing a rationale for clinical trials of these approaches in humans.

Clinicopathological evaluation of PD-L1 expression and cytotoxic T-lymphocyte infiltrates across intracranial molecular subgroups of ependymomas: are these tumors potential candidates for immune check-point blockade?

Immune check-point blockade (ICB) targeting programmed cell death ligand-1 (PD-L1)/programmed death-1 (PD-1) axis has created paradigm shift in cancer treatment. 'ST-RELA' and 'PF-A' molecular subgroups of ependymomas (EPN) show poor outcomes. We aimed to understand the potential candidature of EPNs for ICB. Supratentorial (ST) Grade II/III EPNs were classified into ST-RELA, ST-YAP, and ST-not otherwise specified (NOS), based on RELA/YAP1 fusion transcripts and/or L1CAM and p65 protein expression. Posterior fossa (PF) EPNs were classified into PF-A and PF-B based on H3K27me3 expression. Immunohistochemistry for PD-L1 and CD8 was performed. RelA protein enrichment at PDL1 promoter site was analysed by chromatin immunoprecipitation-qPCR (ChIP-qPCR). Eighty-three intracranial EPNs were studied. Median tumor infiltrating CD8 + cytotoxic T-lymphocyte (CTL) density was 6/mm2, and was higher in ST-EPNs (median 10/mm2) as compared to PF-EPNs (median 3/mm2). PD-L1 expression was noted in 17/83 (20%) EPNs, including 12/31 ST-RELA and rare ST-NOS (2/12), PF-A (2/25) and PF-B (1/13) EPNs. Twelve EPNs (14%) showed high CTL density and concurrent PD-L1 positivity, of which majority (10/12) were ST-RELA EPNs. Enrichment of RelA protein was seen at PDL1 promoter. Increased CTL densities and upregulation of PD-L1 in ST-RELA ependymomas suggests potential candidature for immunotherapy.

Tumor-infiltrating immune cell subpopulations and programmed death ligand 1 (PD-L1) expression associated with clinicopathological and prognostic parameters in ependymoma.

Ependymomas are biologically and clinically heterogeneous tumors of the central nervous system that have variable clinical outcomes. The status of the tumor immune microenvironment in ependymoma remains unclear. Immune cell subsets and programmed death ligand 1 (PD-L1) expression were measured in 178 classical ependymoma cases by immunohistochemistry using monoclonal antibodies that recognized tumor-infiltrating lymphocyte subsets (TILs; CD3, CD4, CD8, FOXP3, and CD20), tumor-associated macrophages (TAMs; CD68, CD163, AIF1), indoleamine 2,3-dioxygenase (IDO)+ cells and PD-L1-expressing tumor cells. Increases in CD3+ and CD8+ cell numbers were associated with a prolonged PFS. In contrast, increased numbers of FOXP3+ and CD68+ cells and a ratio of CD163/AIF1+ cells were significantly associated with a shorter PFS. An increase in the IDO+ cell number was associated with a significantly longer PFS. To consider the quantities of TILs, TAMs, and IDO+ cells together, the cases were clustered into 2 immune cell subgroups using a k-means clustering analysis. Immune cell subgroup A, which was defined by high CD3+, low CD68+ and high IDO+ cell counts, predicted a favorable PFS compared to subgroup B by univariate and multivariate analyses. We found six ependymoma cases expressing PD-L1. All these cases were supratentorial ependymoma, RELA fusion-positive (ST-RELA). PD-L1 expression showed no prognostic significance. This study showed that the analysis of tumor-infiltrating immune cells could aid in predicting the prognosis of ependymoma patients and in determining therapeutic strategies to target the tumor microenvironment. PD-L1 expression in the ST-RELA subgroup suggests that this marker has a potential added value for future immunotherapy treatments.

PD-1/PD-L1 and immune-related gene expression pattern in pediatric malignant brain tumors: clinical correlation with survival data in Korean population.

BACKGROUND: PD-L1 expression has been evaluated as a predictive biomarker for immunotherapy in numerous tumor types. However, very limited data are available in pediatric brain tumors. The aim of this study was to characterize PD-1 and PD-L1 expressions of four pediatric malignant brain tumors and gene expression profile. METHODS: This study included 89 pediatric patients receiving standard treatment at Seoul National University Children's Hospital and Seoul National University Bundang Hospital between 1990 and 2014: atypical teratoid/rhabdoid tumor (AT/RT) 20; ependymoma (EPN) 20; high grade glioma (HGG) 21; and medulloblastoma (MBL) 28. We performed immunohistochemistry assays for PD-1 and PD-L1. To characterize the gene expression, a custom immune-response focused gene panel was used. RESULTS: PD-1 expression was positive in 7 (35%) AT/RT, 7 (35%) EPN, 4 (19%) HGG, and 3 (11%) MBL patients. PD-L1 expression was positive in 8 (40%) AT/RT, 4 (20%) EPN, and 4 (19%) HGG; negative in all MBL patients. There was no statistically significant difference in the overall survival of PD-L1 positive patients. The gene expression analysis demonstrated differences in two clustering functional categories: cell-cell signaling and antigen presentation pathway. CONCLUSIONS: AT/RT, EPN, and HGG showed a relatively higher expression rate of PD-L1 (19-40%). This suggests these tumor types might be good candidates for PD-1 checkpoint blockade. We determined that gene expression may potentially serve as a molecular tool in predicting which patients will respond to immunotherapy. Further investigation is required to better understand the predictive and prognostic role of PD-L1 in pediatric brain tumors.

Resistance-promoting effects of ependymoma treatment revealed through genomic analysis of multiple recurrences in a single patient.

As in other brain tumors, multiple recurrences after complete resection and irradiation of supratentorial ependymoma are common and frequently result in patient death. This standard-of-care treatment was established in the pregenomic era without the ability to evaluate the effect that mutagenic therapies may exert on tumor evolution and in promoting resistance, recurrence, and death. We seized a rare opportunity to characterize treatment effects and the evolution of a single patient's ependymoma across four recurrences after different therapies. A combination of high-depth whole-genome and exome-based DNA sequencing of germline and tumor specimens, RNA sequencing of tumor specimens, and advanced computational analyses were used. Treatment with radiation and chemotherapies resulted in a substantial increase in mutational burden and diversification of the tumor subclonal architecture without eradication of the founding clone. Notable somatic alterations included a MEN1 driver, several epigenetic modifiers, and therapy-induced mutations that impacted multiple other cancer-relevant pathways and altered the neoantigen landscape. These genomic data provided new mechanistic insights into the genesis of ependymoma and pathways of resistance. They also revealed that radiation and chemotherapy were significant forces in shaping the increased subclonal complexity of each tumor recurrence while also failing to eradicate the founding clone. This raises the question of whether standard-of-care treatments have similar consequences in other patients with ependymoma and other types of brain tumors. If so, the perspective obtained by real-time genomic characterization of a tumor may be essential for making effective patient-specific and adaptive clinical decisions.

Molecular sub-group-specific immunophenotypic changes are associated with outcome in recurrent posterior fossa ependymoma.

Better understanding of ependymoma (EPN) biology at relapse is needed to improve therapy at this critical event. Convincing data exist defining transcriptionally distinct posterior fossa (PF) sub-groups A and B at diagnosis. The clinical and biological consequence of these sub-groups at recurrence has not yet been defined. Genome and transcriptome microarray profiles and clinical variables of matched primary and first recurrent PF EPN pairs were used to identify biologically distinct patterns of progression between EPN sub-groups at recurrence. Key findings were validated by histology and immune function assays. Transcriptomic profiles were partially conserved at recurrence. However, 4 of 14 paired samples changed sub-groups at recurrence, and significant sub-group-specific transcriptomic changes between primary and recurrent tumors were identified, which were predominantly immune-related. Further examination revealed that Group A primary tumors harbor an immune gene signature and cellular functionality consistent with an immunosuppressive phenotype associated with tissue remodeling and wound healing. Conversely, Group B tumors develop an adaptive, antigen-specific immune response signature and increased T-cell infiltration at recurrence. Clinical distinctions between sub-groups become more apparent after first recurrence. Group A tumors were more often sub-totally resected and had a significantly shorter time to subsequent progression and worse overall survival. Minimal tumor-specific genomic changes were observed for either PF Groups A or B at recurrence. Molecular sub-groups of PF EPN convey distinct immunobiologic signatures at diagnosis and recurrence, providing potential biologic rationale to their disparate clinical outcomes. Immunotherapeutic approaches may be warranted, particularly in Group A PF EPN.

Characterization of distinct immunophenotypes across pediatric brain tumor types.

Despite increasing evidence that antitumor immune control exists in the pediatric brain, these findings have yet to be exploited successfully in the clinic. A barrier to development of immunotherapeutic strategies in pediatric brain tumors is that the immunophenotype of these tumors' microenvironment has not been defined. To address this, the current study used multicolor FACS of disaggregated tumor to systematically characterize the frequency and phenotype of infiltrating immune cells in the most common pediatric brain tumor types. The initial study cohort consisted of 7 pilocytic astrocytoma (PA), 19 ependymoma (EPN), 5 glioblastoma (GBM), 6 medulloblastoma (MED), and 5 nontumor brain (NT) control samples obtained from epilepsy surgery. Immune cell types analyzed included both myeloid and T cell lineages and respective markers of activated or suppressed functional phenotypes. Immune parameters that distinguished each of the tumor types were identified. PA and EPN demonstrated significantly higher infiltrating myeloid and lymphoid cells compared with GBM, MED, or NT. Additionally, PA and EPN conveyed a comparatively activated/classically activated myeloid cell-skewed functional phenotype denoted in particular by HLA-DR and CD64 expression. In contrast, GBM and MED contained progressively fewer infiltrating leukocytes and more muted functional phenotypes similar to that of NT. These findings were recapitulated using whole tumor expression of corresponding immune marker genes in a large gene expression microarray cohort of pediatric brain tumors. The results of this cross-tumor comparative analysis demonstrate that different pediatric brain tumor types exhibit distinct immunophenotypes, implying that specific immunotherapeutic approaches may be most effective for each tumor type.

Apurinic/apyrimidinic endonuclease is inversely associated with response to radiotherapy in pediatric ependymoma.

Apurinic/apyrimidinic endonuclease (Ap endo) is a key DNA repair activity that confers radiation resistance in human cells. Here we examined the association between Ap endo activity and response to radiotherapy in pediatric ependymomas, tumors for which treatment options are limited and survival rates are only about 50%. We assayed Ap endo activity in 36 ependymomas and expression of Ape1/Ref-1, the predominant Ap endo activity in humans, in 44 tumors by immunostaining. Cox proportional hazards regression models were used to analyze the association of activity or expression with progression-free survival or with overall survival. Activity varied 13-fold and was not associated with tumor or patient characteristics. In univariate models with Ap endo activity entered as a continuous variable, the hazard ratio for progression increased by a factor of 2.18 for every 0.01 unit increase in activity (p ≤ 0.003) in 24 grade II ependymomas. Risk for death increased by a factor of 1.89 (p ≤ 0.02) in the same population. The fraction of Ape1/Ref-1 immunopositive cells varied widely within individual tumors and was not associated with either progression-free or with overall survival. Suppressing Ap endo activity in pediatric ependymoma cells significantly increased radiation sensitivity, suggesting that the association of activity with radiation response reflected, at least in part, repair of radiation-induced DNA lesions. Our data indicate that Ap endo activity is predictive of outcome following radiotherapy, and suggest that Ape1/Ref-1 promotes radiation resistance in pediatric ependymomas. Our findings support the use of inhibitors of Ap endo activity to overcome resistance.

Oncocytic ependymoma: a new morphological variant of high-grade ependymal neoplasm composed of mitochondrion-rich epithelioid cells.

Oncocytomas are defined as tumors containing in excess of 50% large mitochondrion-rich cells, irrespective of histogenesis and dignity. Along the central neuraxis, oncocytomas are distinctly uncommon but relevant to the differential diagnosis of neoplasia marked by prominent cytoplasmic granularity. We describe an anaplastic ependymoma (WHO grade III) with a prevailing oncocytic component that was surgically resected from the right fronto-insular region of a 43-year-old female. Preoperative imaging showed a fairly circumscribed, partly cystic, contrast-enhancing mass of 2 cm × 2 cm × 1.7 cm. Histology revealed a biphasic neoplasm wherein conventional ependymal features coexisted with plump epithelioid cells replete with brightly eosinophilic granules. Whereas both components displayed an overtly ependymal immunophenotype, including positivity for S100 protein and GFAP, as well as "dot-like" staining for EMA, the oncocytic population also tended to intensely react with the antimitochondrial antibody 113-1. Conversely, failure to bind CD68 indicated absence of significant lysosomal storage. Negative reactions for both pan-cytokeratin (MNF 116) and low molecular weight cytokeratin (CAM 5.2), as well as synaptophysin and thyroglobulin, further assisted in ruling out metastatic carcinoma. In addition to confirming the presence of "zipper-like" intercellular junctions and microvillus-bearing cytoplasmic microlumina, electron microscopy allowed for the pervasive accumulation of mitochondria in tumor cells to be directly visualized. A previously not documented variant, oncocytic ependymoma, is felt to add a reasonably relevant novel item to the differential diagnosis of granule-bearing central nervous system neoplasia, in particular oncocytic meningioma, granular cell astrocytoma, as well as metastatic deposits by oncocytic malignancies from extracranial sites.

Immune gene and cell enrichment is associated with a good prognosis in ependymoma.

Approximately 50% of children with ependymoma will suffer from tumor recurrences that will ultimately lead to death. Development of more effective therapies and patient stratification in ependymoma mandates better prognostication. In this study, tumor gene expression microarray profiles from pediatric ependymoma clinical samples were subject to ontological analyses to identify outcome-associated biological factors. Histology was subsequently used to evaluate the results of ontological analyses. Ontology analyses revealed that genes associated with nonrecurrent ependymoma were predominantly immune function-related. Additionally, increased expression of immune-related genes was correlated with longer time to progression in recurrent ependymoma. Of those genes associated with both the nonrecurrent phenotype and that positively correlated with time to progression, 95% were associated with immune function. Histological analysis of a subset of these immune function genes revealed that their expression was restricted to a subpopulation of tumor-infiltrating cells. Analysis of tumor-infiltrating immune cells showed increased infiltration of CD4(+) T cells in the nonrecurrent ependymomas. No genomic sequences for SV40, BK, JC, or Merkel polyomaviruses were found in nonrecurrent ependymoma. This study reveals that up-regulation of immune function genes is the predominant ontology associated with a good prognosis in ependymoma and it provides preliminary evidence of a beneficial host proinflammatory and/or Ag-specific immune response.

High-dose chemotherapy and adoptive immunotherapy in the treatment of recurrent pediatric brain tumors.

Pediatric patients with recurrent brain tumors have a poor prognosis and limited therapeutic options. We investigated the use of high-dose chemotherapy with adoptive immunotherapy for recurrent brain tumors. Three pediatric patients with recurrent brain tumors received high-dose chemotherapy. This was followed by adoptive transfer of ex-vivo expanded T-cells. The T-cells were generated from peripheral blood after immunization with autologous cancer cells. The objectives of this study included (1) establishing the safety and feasibility of this potential treatment, (2) measuring changes in immune response after high-dose chemotherapy and adoptive immunotherapy, and (3) determining whether adoptive immunotherapy would be able to translate into a clinical response. Immune function was tested in all patients at the time of enrollment into the study. Humoral responses to recall antigens delayed-type hypersensitivity (DTH) were intact in all patients. After immunizing patients with autologous cancer cells, peripheral blood lymphocytes were harvested and activated with anti-CD3, expanded in-vitro, and infused post-autologous transplant. Patients received at least three doses of the vaccine, each consisting of an intradermal administration near a draining lymph node at biweekly intervals. Toxicity was limited and well tolerated in all patients. All three patients showed a tumor-specific immune response by serial imaging. Responses were durable at 16, 23, and 48 months, respectively.

Identification of relevant prognostic histopathologic features in 69 intracranial ependymomas, excluding myxopapillary ependymomas and subependymomas.

BACKGROUND: The results of attempts to identify histopathologic parameters that contribute to the clinical outcome of patients with ependymomas have been controversial. This may be due to the relative rareness of ependymomas. Furthermore, in many investigations, myxopapillary ependymomas and subependymomas were included and may have confounded results, because those tumors should be considered clinicopathologic entities distinct from the other ependymomas. METHODS: In this retrospective study, the influence of the histologic subtype of ependymoma and of individual histologic features on the outcome of 69 patients with ependymomas was investigated. Myxopapillary ependymomas, subependymomas, and ependymomas with spinal localizations were excluded from the analysis. The ependymomas were subdivided into cellular, papillary, clear cell, and tanycytic subtypes. The study extended over a period of 30 years. RESULTS: No differences in clinical outcome between the four histologic subtypes of ependymomas were revealed. Neither tumor localization (either infratentorial or supratentorial), patient age, nor gender affected survival. The survival of patients who underwent complete tumor resection differed significantly from that of patients who underwent partial resection. In univariate analysis, the features of nuclear atypia, the mitotic index, and the MIB-1 labeling index (LI) significantly influenced survival. With regard to survival, the presence of microcysts, blood vessel density, and the feature of vascular hyalinization demonstrated a trend but did not reach significance. In multivariate analysis, only the mitotic index and the MIB-1 LI were identified as factors with independent prognostic significance (P = 0.027 and P = 0.023, respectively). Both proliferation indices were correlated strongly with each other. CONCLUSIONS: The results of the univariate analysis indicated that, for patients with intracranial ependymoma, nuclear atypia, the mitotic index, and the MIB-1 LI significantly influenced survival. In the multivariate analysis, the mitotic index and the MIB-1 LI were the only features that had independent prognostic significance. Because both showed strong correlations, only one of them should be included in a grading scheme for intracranial ependymomas.

Immunohistochemical detection of dUTPase in intracranial tumors.

The nuclear isoform of deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase, OMIM *601266, EC 3.6.1.23) is immunohistochemically detectable in all proliferating tissues and may thus be a useful adjunct for the grading of tumors analogous to Ki-67 labeling. A hundred and twenty-seven human intracranial tumors, including 56 astrocytomas, 12 oligodendrogliomas, 8 oligoastrocytomas, 34 meningiomas, 7 ependymomas, and 10 metastatic carcinomas, were stained using the monoclonal rat anti-human dUTPase antibody (clone 3E6) with formalin-fixed and paraffin-embedded tissue. The labeling indices were compared with those obtained with the proliferation marker Ki-67 on parallel tissue sections. All tumors contained dUTPase-positive nuclei, whereas the percentage of positive tumor cells generally increased with grade of malignancy. Meningiomas of higher grades, i.e., World Health Organization (WHO) grades II and III, contained additional cells with cytoplasmic reactivity. There were usually fewer dUTPase- than Ki-67-positive nuclei detectable. Unlike Ki-67, dUTPase was not detectable in mitotic figures. Labeling indices for dUTPase, but not for Ki-67, showed significant differences between all 3 WHO grades of diffuse astrocytomas. In summary, dUTPase staining provides a useful measure of cell proliferation distinct from that offered by Ki-67 labeling. It proved particularly useful for the evaluation of diffuse astrocytomas.

T lymphocyte subsets and immunoglobulins in intracranial tumor patients before and after treatment, and based on histological type of tumors.

It has been reported that nervous system and peripheral immune system communicate with each other and the peripheral immune status is depressed in some intracranial tumor (ICT) patients pre operatively. Little is known about the immune status of intracranial tumor patients during the post operative survival period. We thus investigated total T cells (CD 11+), helper/inducer (CD4+) T cells, suppressor/cytotoxic (CD8+) T cells, B cells (CD19+) and serum immunoglobulins in peripheral blood in certain ICT patients before and after treatment, and based on the histological type of the tumors. Post treatment analysis were conducted 30 days after surgical removal of tumor tissue in benign brain tumor patients and 30 days after chemo therapy (CT)/radiotherapy (RT) following surgical removal of tumor tissue in malignant brain tumor patients. Decreased CD11+, CD4+ and increased CD8+ T cell counts were observed in both benign and malignant tumor cases before treatment compared with control subjects. After treatment, CD4+ T cell count increased and CD8+ T cell count decreased than their pre treatment levels. Serum IgA and IgG levels were decreased in both benign and malignant brain tumor patients before treatment than in control subjects. Serum IgM level has been increased in both benign and malignant tumor patients before and after treatment than in control subjects. Anaplastic malignant astrocytoma, medulloblastoma and glioblastoma multiforme patients showed higher IgM level than astrocytoma, meningioma and ependymoma patients. In conclusions, the depressed host cellular immunity in benign and malignant tumor patients before treatment may be due to the changes in CD4+ and CD8+ counts in addition to tumour specific immunosuppressive factors. Treatment procedures such as surgery, CT and RT may play certain role in the post operative depressed immunosuppression in malignant tumor patients. Humoral immune mechanism (CD19+) in the ICT patients was less markedly affected.

Rapid molecular discrimination between infection with wild-type varicella-zoster virus and varicella vaccine virus.

Varicella-zoster virus (VZV) infection is immunocompromised patients may cause life-threatening complications. Prevention measures include administration of VZV immuloglobulin, acyclovir and live attenuated varicella vaccine. After vaccination, a mild varicella-like exanthem appears in up to 5% of vaccinees. Morphologically this exanthem cannot be differentiated from wild-type (wt) varicella. The risk of virus transmission after varicella vaccination, in contrast to wt varicella, is low, even in immunocompromised patients. We report on a 2-year-old girl with relapse of cereral anaplastic ependymoma, who received one dose of varicella vaccine. Two weeks later, a maculopapular rash developed while she was an inpatient on the oncology ward. Using VZV-specific PCR and restriction fragment length polymorphism (RFLP) analysis, we were able to diagnose wt varicella infection. Thus, appropriate prevention measures (VZV immunoglobulin and acyclovir) were justified for close contacts to prevent virus transmission. No secondary cases occurred.

Systemic activation of the immune system during ganciclovir treatment following intratumoral herpes simplex virus type 1 thymidine kinase gene transfer in an adolescent ependymoma patient.

During ganciclovir treatment of an adolescent ependymoma patient two weeks after intracranial implantation of HSVtk retroviral vector producer cells, increasing numbers of peripheral T- and B-cells were found as well as enhanced T-cell activation and elevated serum levels of interleukin 12 and soluble Fas ligand. These findings suggest the systemic activation of the immune system during ganciclovir treatment in our patient. The induction of an immune response by HSVtk/ganciclovir supports the concept of an anti-tumor vaccination effect by prodrug activating gene therapy systems and may open new promising perspectives for enhancing therapeutic efficiency by combined prodrug activating and immunological gene therapy strategies.

p14ARF protein (FL-132) immunoreactivity in intracranial ependymomas and its prognostic significance: an analysis of 103 cases.

Although clinical and histological criteria for ependymoma prognosis are recognized, studies have reported contradictory results. Prognostic significance based on immunohistochemistry of ependymomas has been described in a few studies and a strong prognostic value of p53 aberrant expression has been established. Recently, p53 regulation has found to be dependent on the function of the pl4ARF gene product, which has been shown to be critically involved in human carcinogenesis. In this study we have examined patients with intracranial ependymomas (n=103) for immunoexpression of the novel antibody FL-132 to human pl4ARF protein. We found that: (1) the polyclonal FL-132 antibody seems to be suitable for studying pl4ARF protein status in routinely processed and paraffin-embedded specimens; (2) decreasing pl4ARF protein expression is associated with patterns of ependymoma biological aggressiveness, i.e., increasing tumor grade, elevated growth fraction and p53 protein accumulation; however, there was no any association between p14 and MDM2 immunoexpression in ependymomas; (3) although the biological events underlying pl4ARF inactivation in ependymal neoplasms are still unclear, FL-132 immunohistochemistry appears to be useful for assessing an individual prognosis in these tumors; when the p14 score was considered as "high" versus "low" (cut-off p14 labeling index at 10%), it represented an independent prognostic factor in both univariate and multivariate analyses (hazard ratio -3.56; P=0.0003); and (4) most beneficial information for evaluation of malignant ependymoma outcome should be elicited from simultaneous immunohistochemical investigation of p14 ARF and p53 in tumor specimen.

Antineuronal nuclei immunohistochemical staining patterns in childhood ependymomas.

NeuN, the mouse-derived monoclonal antibody to the reportedly neuron-specific nuclear protein, has been observed to react with many different types of normal, postmitotic neurons throughout the central and peripheral nervous systems. We retrospectively examined 23 surgical specimens (collected from 20 patients) originally diagnosed at our institution between 1983 and 1999 as ependymoma (9), myxopapillary ependymoma (1), anaplastic/malignant ependymoma (10), and primitive neuroectodermal tumor with ependymal differentiation (3). The ependymomas included lesions from the spine (3), cerebrum (5), and posterior fossa (15). Representative formalin-fixed, paraffin-embedded sections from each tumor were subjected to immunohistochemical staining with antibody against NeuN (Chemicon International, Inc, Temecula, CA). Five astrocytomas, four primitive neuroectodermal tumors, and normal cerebral cortex and ependyma from autopsy brains of premature newborns, term infants, and older children served as controls. Thirteen ependymal tumors had positive nuclear staining ranging from rare tumor cells to numerous groups of cells; of these, 9 were anaplastic ependymomas and had the most staining. These studies suggest that some ependymomas arise from a pluripotential neuroglial cell.

CD99 immunoreactivity in ependymoma.

The expression of CD99 in normal ependymal cells and ependymoma has been reported. However, only limited numbers of tumors have been studied, and the pattern of CD99 expression has not been described. The authors' purpose was to investigate CD99 immunoreactivity in ependymoma and its use for differential diagnosis. Twenty-five ependymomas were immunostained with antibody directed at CD99. The result of immunostaining of ependymomas was compared with 63 nonependymal tumors that histologically resemble ependymal neoplasms. The nonependymal tumors included 19 astrocytic tumors, 6 oligodendroglial tumors, 8 choroid plexus neoplasms, 2 central neurocytomas, 5 medulloblastomas, 10 primitive neuroectodermal tumors (PNET), and 13 pituitary adenomas. All ependymomas showed strong expression of CD99 in membranous pattern with intracytoplasmic or intercellular dots (ICDs). The expression pattern of CD99 was not correlated with histologic type or grade of ependymomas. Among 63 nonependymal tumors, 11 (17.5%) showed incomplete membrane staining for CD99; diffuse in 4 PNETs and focal in 5 choroid plexus neoplasms (3 papillomas and 2 carcinomas) and one each of pituitary adenoma and oligodendroglioma. The ICD was not found in nonependymal tumors except a case of choroid plexus papilloma. However, membrane staining or ICD for CD99 was not distinctive in nonependymal tumors. In conclusion, the characteristic pattern of anti-CD99 antibody, i.e., diffuse strong membranous immunostaining with ICDs, is useful in distinguishing ependymomas from the central nervous system tumors that histologically mimic ependymoma.