Primitive Neuroectodermal Tumor Cell Research Articles

Cell-binding IgM in CSF is distinctive of multiple sclerosis and targets the iron transporter SCARA5.

Intrathecal IgM production in multiple sclerosis is associated with a worse disease course. To investigate pathogenic relevance of autoreactive IgM in multiple sclerosis, CSF from two independent cohorts, including multiple sclerosis patients and controls, were screened for antibody binding to induced pluripotent stem cell-derived neurons and astrocytes, and a panel of CNS-related cell lines. IgM binding to a primitive neuro-ectodermal tumour cell line discriminated 10% of multiple sclerosis donors from controls. Transcriptomes of single IgM producing CSF B cells from patients with cell-binding IgM were sequenced and used to produce recombinant monoclonal antibodies for characterization and antigen identification. We produced five cell-binding recombinant IgM antibodies, of which one, cloned from an HLA-DR + plasma-like B cell, mediated antigen-dependent complement activation. Immunoprecipitation and mass spectrometry, and biochemical and transcriptome analysis of the target cells identified the iron transport scavenger protein SCARA5 as the antigen target of this antibody. Intrathecal injection of a SCARA5 antibody led to an increased T cell infiltration in an experimental autoimmune encephalomyelitis (EAE) model. CSF IgM might contribute to CNS inflammation in multiple sclerosis by binding to cell surface antigens like SCARA5 and activating complement, or by facilitating immune cell migration into the brain.

Undifferentiated Melanoma: A Rare Phenomenon and a Challenging Diagnosis

Abstract Introduction/Objective Undifferentiated melanoma is defined as a primary or metastatic melanoma lacking histologic and immunophenotypic features of melanoma. Dedifferentiated melanoma shows transition between undifferentiated and conventional melanoma components. Dedifferentiation and transdifferentiation (implying dedifferentiation with heterologous elements) in melanoma are exceedingly rare and occur mostly in metastatic deposits. The purpose of this report is to describe a case of undifferentiated melanoma that proved to be a diagnostic challenge and to highlight the importance of the multimodality approach and utilization of advanced diagnostic tools in reaching an accurate diagnosis. Methods/Case Report Methods: A 43-year-old white male who was diagnosed with metastatic melanoma on the right axillary biopsy at a local hospital presented to our institution with a rapidly enlarging 30 cm peritoneal mass. He underwent debulking surgery to lower his tumor burden. On pathologic evaluation, the tumor showed a heterogeneous appearance ranging from highly cellular fascicles of spindle cells to sheets of primitive round cells and epithelioid cells with abundant eosinophilic cytoplasm. One metastatic focus showed heterologous cartilaginous differentiation. This morphologic appearance elicited the differential diagnosis of metastatic melanoma, primitive neuroectodermal tumor, synovial sarcoma, and metastatic germ cell tumor with somatic transformation. Immunochemical staining showed the tumor cells to be positive for SALL4, CD99 (patchy), and TLE1 (patchy) and negative for pan-cytokeratin, S100, SOX- 10, HMB-45, desmin, myogenin, DOG1, CD 117, CDX2, TTF-1, PAX-8, CK7, CK20, chromogranin, CD30, and OCT4. Fluorescence in situ hybridization for EWSR1, SS18(SYT), and isochromosome 12p were negative. BRAF gene mutation analysis detected p.V600E / p.V600D. Subsequently, a diagnosis of undifferentiated melanoma was rendered after expert consultation. Unfortunately, the patient passed away 1 month after surgery. Results (if a Case Study enter NA) NA. Conclusion Diagnosis of undifferentiated melanoma by the conventional H&E and immunohistochemical profile is extremely challenging. Multimodality approach and utilization of advanced diagnostic tools such as molecular studies are helpful in this regard.

DICER1-associated Tumors in the Female Genital Tract: Molecular Basis, Clinicopathologic Features, and Differential Diagnosis.

DICER1 syndrome is a tumor predisposition syndrome in which patients are at an increased risk of developing a wide variety of benign and malignant neoplasms with a hallmark constellation of pediatric pleuropulmonary blastoma, cystic nephroma, and thyroid lesions. DICER1 encodes an RNA endoribonuclease that is crucial to the processing of microRNA and may play a role in the maturation of Müllerian tissue. Within the gynecologic tract, germline mutations in DICER1 are associated with an array of rare tumors, including Sertoli-Leydig cell tumor, embryonal rhabdomyosarcoma of the cervix, gynandroblastoma, and juvenile granulosa cell tumor, which typically present in childhood, adolescence, or early adulthood. In addition, somatic DICER1 mutations have been described in rare gynecologic tumors such as adenosarcoma, Sertoli cell tumor, ovarian fibrosarcoma, cervical primitive neuroectodermal tumor, carcinosarcoma, and germ cell tumors. In light of the significant association with multiple neoplasms, genetic counseling should be considered for patients who present with a personal or family history of these rare DICER1-associated gynecologic tumors. This review highlights the most current understanding of DICER1 genetic alterations and describes the clinical, histopathologic, and immunohistochemical features and differential diagnoses for gynecologic tumors associated with DICER1 mutation.

Primitive Neuroectodermal Tumor of Maxilla in a 4-year-old Child

Primitive neuroectodermal tumor (PNET) belongs to the class of malignant round cell tumor. PNETs show varying degree of neuroectodermal differentiation. They are one of the most common tumors of childhood occurring in bone and also within soft tissues. Light microscopy with the aid of immunohistochemical stains was suitable for the diagnosis. Immunohistochemistry plays a pivotal role in differentiating this tumor entity. The EWSR1-FLI1 fusion is present only in PNET cells and codes for oncogenic protein. In this article, we present a case of maxillary swelling in a 4-year-old girl child who was diagnosed with PNET. We have highlighted the challenges of diagnosing the round cell tumors.

Comparison of Aggressive Pattern in Ewing Sarcoma and Primitive Neuroectodermal Tumor Cell Lines

Comparison of Aggressive Pattern in Ewing Sarcoma and Primitive Neuroectodermal Tumor Cell Lines

ZBTB16: A new biomarker for primitive neuroectodermal tumor element / Ewing sarcoma

Primitive neuroectodermal tumor (PNET) traditionally encompasses two different classes of tumors with similar morphology - PNET of the peripheral nervous system (pPNET) and PNET of the central nervous system (cPNET). The latter also includes germ cell tumor-derived PNET (gPNET). There are currently no specific markers for gPNET. This study seeks to investigate the expression of ZBTB16 in PNET and other small round blue cell tumors as well as its potential diagnostic utility. Immunohistochemical expression of the ZBTB16 was studied in a total of 27 PNETs (12 pPNETs, 8 cPNETs, 3 primary testicular gPNETs, and 4 metastatic gPNETs) and 38 small round blue cell tumors. Positive expression for ZBTB16 was seen diffusely in 9/12 (75%), moderately in 2/12 (17%) and focally in 1/12 (8%) of pPNETs, diffusely in 3/7 (43%) and moderately in 4/7 (57%) of gPNETs, and diffusely in 2/8 (25%), moderately in 2/8 (25%) and focally in 4/8 (50%) of cPNETs. Whereas, all of the 38 non-PNET small round blue cell tumors were nonreactive. The results suggest that ZBTB16 is a highly sensitive and specific biomarker for both pPNET and gPNET/cPNET. ZBTB16 effectively differentiates PNETs from other small round blue cell tumor mimics, including the two most common germ cell tumor-derived somatic malignancies - rhabdomyosarcoma and nephroblastoma. Of note, compared to the expression of ZBTB16 in pPNET/Ewing sarcoma and gPNET, the expression of ZBTB16 in cPNET was more variable, which appears consistent with the heterogeneity of cPNET. The close proximity of ZBTB16 and FLI-1 genes on chromosome 11q may explain the overexpression of ZBTB16 in PNET, especially in pPNET with t(1122) translocation.

Image-guided Fine Needle Aspiration Cytology of Intrathoracic Lesions.

Background:Percutaneous, image-guided transthoracic fine needle aspiration cytology (TTFNAC) is a rapid, yet accurate, and well-established diagnostic method used in the cytological evaluation of intrathoracic lesions. The study was done to determine the utility of image-guided TTFNAC in diagnosis of intrathoracic lesions.Subjects and Methods:A retrospective analysis of all cases who underwent image-guided TTFNAC of a suspected intrathoracic lesion, in a tertiary care hospital was done over a period of 3 years.Results:During the study period, 124 cases of image-guided FNAC of intrathoracic lesions were obtained. The mean age at presentation was 60.5 years with M:F: 3.6:1. Neoplastic lesions (71.5%) outnumbered the nonneoplastic lesions (28.5%). The most common tumor was adenocarcinoma (25%) followed by squamous cell carcinoma (SCC, 11%), and small cell carcinoma (5%). There was one case each of anaplastic carcinoma, plasmacytoma, bronchoalveolar carcinoma, and non-Hodgkin lymphoma (NHL). Most of the lesions were found on the right side and upper lobe. Among the mediastinal lesions, we found two cases of thymoma and one case each of NHL)/primitive neuroectodermal tumor (PNET), NHL, and small cell carcinoma metastasis to lymph node followed by ten cases of inflammatory lesions and seven cases of tuberculosis (TB).Conclusion:Image-guided TTFNAC of intrathoracic lesions is a safe method when done by well-trained medical personnel with lesser rate of complications. An early accurate diagnosis of malignancy can be made based on the cytological features; however, further subtyping of the malignancy may sometimes be difficult due to overlapping cytological features. TTFNAC can be a diagnostic tool for identifying nonneoplastic lesion such as TB. Hence, image-guided FNAC aids in early diagnosis and management of patients with intrathoracic lesions.

Abstract A19: Epigenetic drug combination induces genome-wide demethylation and altered gene expression in neuro-ectodermal tumor-derived cell lines

Abstract Background: Epigenetic alterations are inherent to cancer cells, and epigenetic drugs are currently primarily used to treat hematological malignancies. Pediatric neuro-ectodermal tumors originate from neural crest cells and also exhibit epigenetic alterations involving e.g. apoptotic pathways, which suggests that also these tumors may be sensitive to epigenetic drugs. This notion prompted us to assess molecular and functional effects of low dosage epigenetic drugs in neuro-ectodermal tumor-derived cell lines of pediatric origin. Results: In 17 neuroblastoma (NBL) and 5 peripheral primitive neuro-ectodermal tumor (PNET) cell lines a combination treatment of 5-aza-2′-deoxycytidine (DAC) and Trichostatin A (TSA) at nanomolar dosages was found to reduce proliferation and to induce wide-spread DNA demethylation, accompanied by major changes in gene expression profiles. Approximately half of the genes that were significantly up-regulated upon treatment exhibited a significant demethylation in their promoter regions. In the NBL cell lines, almost every cellular pathway (193/200) investigated showed expression alterations after treatment, especially a marked up-regulation of genes in the p53 pathway. The combination treatment also resulted in up-regulation of known epigenetically regulated genes such as X-chromosomal genes, tissue-specific genes and a limited number of imprinted genes, as well as known tumor suppressor genes and oncogenes. Conclusions: Nanomolar dosages of epigenetic drugs have a dramatic impact on the genomes of neuro-ectodermal tumor derived cell lines, including alterations in DNA methylation and concomitant alterations in gene expression. Citation Format: Max M. van Noesel, Floor A M Duijkers, Renee X. de Menezes, Dominique J. P. M. Stumpel, Pieter Admiraal, Rob Pieters, Jules P P Meijerink. Epigenetic drug combination induces genome-wide demethylation and altered gene expression in neuro-ectodermal tumor-derived cell lines. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A19.

A prognostic analysis of pediatrics central nervous system small cell tumors: evaluation of EGFR family gene amplification and overexpression.

BackgroundCentral nervous system (CNS) tumors are the most common solid tumors that occur in children, however there were few big-data follow-up analysis published in China. Overexpression of epidermal growth factor receptor (EGFR) family members was reported on glioblastoma (GBM) and medulloblastoma (MB) before. However, the correlation between EGFR family members expression with prognosis of MB, supratentorial primitive neuroectodermal tumor (PNET) and small cell GBM is unclear in Chinese children.MethodsA retrospective and survival analysis was performed on children (age ≤ 16 years) diagnosed as CNS primary small cell tumors in the Affiliated Provincial Hospital, Shandong University from 2000 to 2012, including MB (n = 44), PNET (n = 8) and small cell GBM (n = 19). The expression of EGFR, ERBB-2, ERBB-3 and ERBB-4 were detected by immunohistochemistry (IHC). The fluorescence in situ hybridization (FISH) was used to observe the amplification of EGFR and ERBB-2 gene.ResultsMedian survival times of MBs, small GBMs and PNETs were 23 ± 6.7 months, 8 ± 4.7 months and 10 ± 1.4 months. Expression and amplification of ERBB-2, ERBB-3 and ERBB-4 were not observed in all tumor samples. The multiply Cox regression suggested the overexpression and amplification of EGFR were negative prognostic factors for MB. Radiotherapy had the positive function for all pediatric patients.ConclusionOverexpression of EGFR predicts poor outcomes of MBs, small cell GBMs and PNETs, suggesting those three CNS tumor subtypes can be considered as one group for the potential common mechanism. The current individual treatment and big data analysis of pediatric CNS embryonal tumors and GBM continues to be very challenging in China.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7649640001237474

Cellular mesenchymal tumors of the uterus: a review emphasizing recent observations.

Cellular mesenchymal tumors of the uterus may be divided in 2 main groups, smooth muscle and endometrial stromal. Among the former, highly cellular leiomyoma is the classic example. This tumor is not infrequently confused with an endometrial stromal tumor due to its often yellow color and soft consistency, dense cellularity, striking vascularity, not uncommon irregular margin and even rarely association with seedling cellular leiomyomas, both mimicking the infiltration of a low-grade endometrial stromal sarcoma. Cellular intravenous leiomyomatosis can also mimic endometrial stromal sarcoma due to their shared intravascular growth. A variety of histologic features typical of cellular smooth muscle including clefts and differing vasculature help in this distinction. Although endometrial stromal tumors are typically highly cellular, recent studies have expanded their spectrum to include those that are less so due to smooth muscle metaplasia, fibrous and myxoid change, and even oxyphilic cytoplasm. A subset now designated high-grade endometrial stromal sarcoma showing a t(10;17) has been characterized to show small epithelioid cells associated with brisk miotic activity, typically being CD10, ER and PR negative, and cyclin D1 positive. These tumors are juxtaposed to areas of fibromyxoid endometrial stromal neoplasia in 50% of cases. An enigmatic category of uterine mesenchymal neoplasms, often densely cellular, are those descriptively referred to as "uterine tumors resembling ovarian sex cord tumors." Their spectrum is briefly noted as is their crucial distinction from stromal sarcoma with sex cord-like differentiation. Other tumors that rarely occur in the uterus that are densely cellular include but are not limited to undifferentiated uterine sarcoma, embryonal rhabdomyosarcoma, primitive neuroectodermal tumor, lymphoma or small cell, or undifferentiated carcinoma. In this essay, I review the most helpful morphologic, immunohistochemical, and/or cytogenetic features in the diagnosis of each one of these entities.

Expulsion of micronuclei containing amplified genes contributes to a decrease in double minute chromosomes from malignant tumor cells

Double minute chromosomes (DMs) are a hallmark of gene amplification. The relationship between the formation of DMs and the amplification of DM-carried genes remains to be clarified. The human colorectal cancer cell line NCI-H716 and human malignant primitive neuroectodermal tumor cell line SK-PN-DW are known to contain many DMs. To examine the amplification of DM-carried genes in tumor cells, we performed Affymetrix SNP Array 6.0 analyses and verified the regions of amplification in NCI-H716 and SK-PN-DW tumor cells. We identified the amplification regions and the DM-carried genes that were amplified and overexpressed in tumor cells. Using RNA interference, we downregulated seven DM-carried genes, (NDUFB9, MTSS1, NSMCE2, TRIB1, FAM84B, MYC and FGFR2) individually and then investigated the formation of DMs, the amplification of the DM-carried genes, DNA damage and the physiological function of these genes. We found that suppressing the expression of DM-carried genes led to a decrease in the number of DMs and reduced the amplification of the DM-carried genes through the micronuclei expulsion of DMs from the tumor cells. We further detected an increase in the number of γH2AX foci in the knockdown cells, which provides a strong link between DNA damage and the loss of DMs. In addition, the loss of DMs and the reduced amplification and expression of the DM-carried genes resulted in a decrease in cell proliferation and invasion ability.

Epigenetic drug combination induces genome-wide demethylation and altered gene expression in neuro-ectodermal tumor-derived cell lines

Epigenetic alterations are inherent to cancer cells, and epigenetic drugs are currently primarily used to treat hematological malignancies. Pediatric neuro-ectodermal tumors originate from neural crest cells and also exhibit epigenetic alterations involving e.g. apoptotic pathways, which suggests that these tumors may also be sensitive to epigenetic drugs. This notion prompted us to assess molecular and functional effects of low dosage epigenetic drugs in neuro-ectodermal tumor-derived cell lines of pediatric origin. In 17 neuroblastoma (NBL) and 5 peripheral primitive neuro-ectodermal tumor (PNET) cell lines a combination treatment of 5-aza-2'-deoxycytidine (DAC) and Trichostatin A (TSA) at nanomolar dosages was found to reduce proliferation and to induce wide-spread DNA demethylation, accompanied by major changes in gene expression profiles. Approximately half of the genes that were significantly up-regulated upon treatment exhibited a significant demethylation in their promoter regions. In the NBL cell lines, almost every cellular pathway (193/200) investigated showed expression alterations after treatment, especially a marked up-regulation of genes in the p53 pathway. The combination treatment also resulted in up-regulation of known epigenetically regulated genes such as X-chromosomal genes, tissue-specific genes and a limited number of imprinted genes, as well as known tumor suppressor genes and oncogenes. Nanomolar dosages of epigenetic drugs have a dramatic impact on the genomes of neuro-ectodermal tumor-derived cell lines, including alterations in DNA methylation and concomitant alterations in gene expression.

Abstract 5051: MYC-driven models of primitive neuroectodermal tumor are sensitive to inhibitors of glutamine metabolism.

Abstract Brain tumors are a diverse group of cancers in which alterations in growth regulation pathways drive tumorigenicity. Histologically similar tumors may have significant differences in underlying molecular pathways and this in turn may have significant implications for the development of targeted treatment. The MYC family of proteins promotes proliferation and an aggressive phenotype in diverse cancers. Primitive Neuroectodermal Tumors (PNETs) are high grade tumors that can arise throughout the neuro-axis. One subset of PNETs is MYC amplified, and some PNETs are known to express LIN28A, a key regulator of MYC. MYC expression in tumors leads to increased reliance on glutamine metabolism (i.e. the Warburg effect). We hypothesized that MYC-driven PNET tumors would up regulate glutamine metabolism and that glutaminase inhibitors would selectively target MYC-driven tumors. We tested this hypothesis using the MYC-positive PNET cell line PFSK as well as MYC-transformed human neural stem cells. The glutamine methabolic inhibitors DON (6-Diazo-5-oxo-L-norleucine) and acivicin were used to disrupt glutamine metabolism in these cells. Using Tetrazolium dye reduction (MTT assay) and Bromodeoxyuridine assays (BrdU) as indicators for cell growth and replication, we found that PFSK growth is inhibited by acivicin at 10 micromolar concentration (MTT activity reduced by 88%, p<0.05, t-test acivicin treated compared to untreated) MYC-negative UW228 cells were resistant to DON and acivicin treatment. Similarly, DON or acivicin inhibited the proliferation of MYC-transformed human neural stem cells. We observed a 75% reduction in BrdU incorporation in MYC transformed cortex neural stem cells using acivicin, (p<0.001, t-test acivicin treated compared to vehicle treated), 60% reduction in cortex MYC cells using DON (p<0.05), and a 48% reduction in hindbrain MYC cells using DON (p<0.01). The growth of control MYC-negative cells was not significantly inhibited by either drug. This data shows that glutaminase inhibition limits cell replication in tissue culture models of MYC-driven PNET. We are currently investigating the mechanism of growth inhibition (e.g. apoptosis versus cell cycle arrest) caused by glutaminase inhibitors. Murine orthotopic xenograft experiments investigating the efficacy of DON and acivicin treatment in MYC-driven PNET are currently underway in our laboratory. Citation Format: Sama F. Ahsan, Allison Hanaford, Melanie Weingart, Isabella Taylor, Charles Eberhart, Eric Raabe. MYC-driven models of primitive neuroectodermal tumor are sensitive to inhibitors of glutamine metabolism. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5051. doi:10.1158/1538-7445.AM2013-5051

Increased unsaturation of lipids in cytoplasmic lipid droplets in DAOY cancer cells in response to cisplatin treatment

Increases in 1H nuclear magnetic resonance spectroscopy (NMR) visible lipids are a well-documented sign of treatment response in cancers. Lipids in cytoplasmic lipid droplets (LDs) are the main contributors to the NMR lipid signals. Two human primitive neuroectodermal tumour cell lines with different sensitivities to cisplatin treatment were studied. Increases in NMR visible saturated and unsaturated lipids in cisplatin treated DAOY cells were associated with the accumulation of LDs prior to DNA fragmentation due to apoptosis. An increase in unsaturated fatty acids (UFAs) was detected in isolated LDs from DAOY cells, in contrast to a slight decrease in UFAs in lipid extracts from whole cells. Oleic acid and linoleic acid were identified as the accumulating UFAs in LDs by heteronuclear single quantum coherence spectroscopy (HSQC). 1H NMR lipids in non-responding PFSK-1 cells were unchanged by exposure to 10 μM cisplatin. These findings support the potential of NMR detectable UFAs to serve as a non-invasive marker of tumour cell response to treatment.

Supratentorial Primitive Neuroectodermal Tumors (PNETs) and Medulloblastoma in Children and the Elderly: A Surveillance, Epidemiology, and End Results (SEER) Investigation of Prognosis, Tumor Characteristics, and Predictors of Radiation Therapy

Medulloblastoma and supratentorial PNET predominantly occur in children. Variations in histology, location, prognosis, and radiation treatment (RT) by age are poorly understood. Additionally, a significant portion of patients >3 years (y) do not undergo RT, and we attempted to determine factors associated with this treatment strategy. Using the SEER 1973-2008 database, we identified 2999 CNS supratentorial PNET/pineoblastomas (14.7%) and medulloblastomas (85.3%). Multivariate analysis (covariates: age, sex, tumor site, stage, histology, extent of surgery, RT, and diagnosis year) with Cox proportional hazards and logistic regression identified predictors of survival and radiation treatment, respectively. Median follow-up was 45 months (range 1-428). At diagnosis, age distributions were <3 (N=490), 3-17 (N=1560), 18-34 (N=604), 35-64 (N=315), and ≥65y (N=30). For ≥65 vs. <18y, there were more pineoblastomas (33.3% vs. 4.4%), supratentorial tumors (60.0% vs. 12.8%), and no surgical resection (36.7% vs. 4.8%); all P<0.001. By age, RT administration was: <3 (34.8%), 3-17 (86.9%), 18-34 (85.5%), 35-64 (83.3%), and ≥65y (60.0%); P<0.001. 5y overall (OS) and disease specific survival (DSS) were 60.3% and 63.1%. Histologies with worse 5y OS were supratentorial PNET (40.1%), pineoblastomas (53.5%), and large cell medulloblastomas (53.7%). By location, 5y OS was 65.0% for infratentorial, 47.2% for supratentorial, and 48.7% for primary spinal cord lesions. When examining 5y DSS by age group, elderly patients had the lowest DSS (17.5%), followed by <3 (47.8%), 3-17 (67.5%), 18-34 (67.0%), and 35-64y (59.9%). In multivariate analysis (3-17y reference, HR=1), patients <3 (HR 1.34), 35-64 (HR 1.50), and ≥65 (HR 2.16) had worse DSS (P<0.01). 5y OS with and without RT was 64.9% and 43.8%, respectively (P<0.001). For DSS after adjustment, significant (P<0.05) disease factors associated with decreased survival were supratentorial location (HR 1.79), distant metastases (HR 1.73), PNET histology (HR 1.58) and large cell medulloblastoma (HR 2.73). Significant treatment factors for improved DSS were gross total resection (HR 0.72) and RT (HR 0.54). In multivariate analysis (3-17y reference OR=1), only age was associated with RT use, with those <3y (OR 0.08) and ≥65 (OR 0.33) less likely to receive RT at initial diagnosis (P<0.05). Characteristics underlying prognosis of supratentorial PNET and medulloblastoma differ by age. Among elderly patients there is a greater proportion of pineoblastomas, supratentorial PNETs, and less aggressive use of surgery and RT, potentially contributing to worse survival in this high-risk population.

Abstract 5212: Irradiation-induced uPAR promotes stemness via Wnt/β-catenin signaling in medulloblastoma cells

Abstract Urokinase plasminogen activator receptor (uPAR) is known to promote invasion, migration and metastasis in cancer cells. In this study, we show that ionizing radiation (IR) induced uPAR has a role in Wnt/β-catenin signaling and mediates induction of cancer stem cells (CSC)-like properties in medulloblastoma cell lines UW228 and D283. We observed that IR induced the expression of uPAR, CSC markers such as CD44 and Msi-1, and activates Wnt/β-catenin signaling molecules. Overexpression of uPAR after IR treatment led to the activation of Wnt signaling, which was demonstrated by an increase in nuclear translocation of β-catenin and β-catenin-Lef/Tcf-mediated transactivation, thereby promoting cancer stemness. Quercetin, a potent Wnt/β-catenin inhibitor suppressed uPAR and uPAR-mediated Wnt/β-catenin activation. Treatment with shRNA specific for uPAR (pU) suppressed the β-catenin-Tcf/Lef-mediated transactivation both in vitro and in vivo. Further, we show that uPAR is physically associated with the Wnt effector molecule β-catenin using immunocytochemistry and immunohistochemistry; these results were confirmed by immunoprecipitation analysis. Most interestingly, we demonstrate for the first time that the localization of uPAR in the nucleus is associated with transcription factors (TF) and their specific response elements. The association of uPAR with β-catenin-Tcf/Lef complex and various other TF involved in neurogenesis during embryonic development and cancer demonstrates the receptor's possible role at generating CSC-like properties in primitive neuroectodermal tumor (PNET) cells of medulloblastoma. Considering all of the data, we conclude that uPAR is a potent activator of stemness, and the targeting of uPAR in combination with radiation has significant therapeutic implications. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5212. doi:1538-7445.AM2012-5212

Embryonal tumor with abundant neuropil and true rosettes (ETANTR) with loss of morphological but retained genetic key features during progression

Embryonal tumor with abundant neuropil and true rosettes (ETANTR) is a recently recognized, rare embryonal CNS tumor, which predominantly occurs in young children and is associated with a highly aggressive disease course [1–3, 5–8, 13, 14, 18, 19, 23]. The histopathological diagnosis of ETANTR is based on the presence of primitive neuroectodermal tumor cells forming distinct multilayered ‘ependymoblastic’ rosettes and characteristic neuropil islands. Recently, genome-wide analyses have revealed a novel amplification at 19q13.42 [16, 19], which is meanwhile considered the genetic hallmark of ETANTR [13, 16]. The characteristic clinical, morphological, and genetic features support the concept of a distinct CNS PNET variant and suggest its introduction to the WHO classification of Tumors of the Central Nervous System [17]. As the amplification at 19q13.42 has also been found in the vast majority of ependymoblastomas analyzed to date [13, 16], the common genetic background suggests the fusion of these two tumor types to a single entity. Herein, we report for the first time the evolution of morphological features and genetic aberrations during the disease course in a patient with ETANTR. A 33-monthold girl presented with a 6-month history of episodic headaches, increased head circumference and mild gait disturbance. Magnetic resonance (MR) imaging showed a 9.6 9 8.6 9 11.7 cm left parieto-occipital, space-occupying, partly cystic lesion displaying T1-weighted hypoto isointense signals (Fig. 1a) with cerebrospinal fluid-intense cysts on FLAIR sequence (Fig. 1b), and marked choline/ creatine increase as a sign of cell proliferation on single voxel spectroscopy (Fig. 1c). Near-total surgical resection was performed. Histopathology revealed a primitive neuroectodermal tumor with highly cellular areas. Furthermore, hypocellular neuropil islands and multilayered rosettes were

Characteristics of human Ewing/PNET sarcoma models

Ewing/PNET (peripheral neuroepithelioma) tumors are rare aggressive bone sarcomas occurring in young people. Rare-disease clinical trials can require global collaborations and many years. In vivo models that as accurately as possible reflect the clinical disease are helpful in selecting therapeutics with the most promise of positive clinical impact. Human Ewing/PNET sarcoma cell lines developed over the past 45 years are described. Several of these have undergone genetic analysis and have been confirmed to be those of Ewing/PNET sarcoma. The A673 Ewing sarcoma line has proven to be particularly useful in understanding the biology of this disease in the mouse. The chromosomal translocation producing the EWS/FLI1 fusion transcript characterizes clinical Ewing sarcoma. Cell lines that express this genetic profile are confirmed to be those of Ewing sarcoma. The A673 Ewing sarcoma line grows in culture and as a xenograft in immunodeficient mice. The A673 model has been used to study Ewing sarcoma angiogenesis and response to antiangiogenic agents. Many Ewing sarcoma clinical specimens express the cell surface protein endosialin. Several Ewing sarcoma cell lines, including the A673 line, also express cell surface endosialin when grown as subcutaneous tumor nodules and as disseminated disease; thus the A673 is a useful model for the study of endosialin biology and endosialin-directed therapies. With the advent of tools that allow characterization of clinical disease to facilitate optimal treatment, it becomes imperative, especially for rare tumors, to develop preclinical models reflecting disease subsets. Ewing PNET sarcomas are a rare disease where models are available.

Expression of O6-methylguanine-DNA methyltransferase in childhood medulloblastoma

Medulloblastomas (MB) are the most common malignant brain tumors in childhood. Alkylator-based drugs are effective agents in the treatment of patients with MB. In several tumors, including malignant glioma, elevated O(6)-methylguanine-DNA methyltransferase (MGMT) expression levels or lack of MGMT promoter methylation have been found to be associated with resistance to alkylating chemotherapeutic agents such as temozolomide (TMZ). In this study, we examined the MGMT status of MB and central nervous system primitive neuroectodermal tumor (PNET) cells and two large sets of primary MB. In seven MB/PNET cell lines investigated, MGMT promoter methylation was detected only in D425 human MB cells as assayed by the qualitative methylation-specific PCR and the more quantitative pyrosequencing assay. In D425 human MB cells, MGMT mRNA and protein expression was clearly lower when compared with the MGMT expression in the other MB/PNET cell lines. In MB/PNET cells, sensitivity towards TMZ and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) correlated with MGMT methylation and MGMT mRNA expression. Pyrosequencing in 67 primary MB samples revealed a mean percentage of MGMT methylation of 3.7-92% (mean: 13.25%, median: 10.67%). Percentage of MGMT methylation and MGMT mRNA expression as determined by quantitative RT-PCR correlated inversely (n = 46; Pearson correlation r (2) = 0.14, P = 0.01). We then analyzed MGMT mRNA expression in a second set of 47 formalin-fixed paraffin-embedded primary MB samples from clinically well-documented patients treated within the prospective randomized multicenter trial HIT'91. No association was found between MGMT mRNA expression and progression-free or overall survival. Therefore, it is not currently recommended to use MGMT mRNA expression analysis to determine who should receive alkylating agents and who should not.

Cathepsin B facilitates autophagy-mediated apoptosis in SPARC overexpressed primitive neuroectodermal tumor cells

Medulloblastoma and neuroblastoma belong to a group of neoplasms designated as primitive neuroectodermal tumors (PNETs). Secreted protein, acidic and rich in cysteine (SPARC) is a matrix-associated glycoprotein that influences a variety of cellular activities in vitro and in vivo. In this study, we provide evidence that expression of SPARC cDNA induces autophagy in PNET cells followed by apoptotic cell death. SPARC-induced autophagy was morphologically characterized by (i) the formation of membrane-bound autophagic vacuoles (AVOs), (ii) increase in the levels of microtubule-associated protein light chain 3 (LC3) and (iii) induction of the lysososmal enzyme cathepsin B. Cathepsin B, in turn induced mitochondrial release of cytochrome c and activated caspase-3, events that signify the onset of apoptotic cell death. In agreement with these observations, inhibition of autophagy by 3-MA reduced AVO formation and LC3 and inhibited apoptosis, suggesting that autophagy has a role in SPARC-mediated apoptosis. Blocking cathepsin B expression with a specific inhibitor of cathepsin B suppressed apoptosis but did not affect autophagy, which suggests that cathepsin B is a molecular link between autophagy and apoptosis. In summary, these findings show that SPARC expression induces autophagy, which results in the elevation of cathepsin B and subsequent mitochondria-mediated apoptosis.