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Analysis of the GAP-related domain of the neurofibromatosis type 1 (NF1) gene in childhood brain tumors.

The neurofibromatosis type-1 (NF1) gene contains a 360-bp region with significant homology to the catalytic domain of mammalian GTPase-activating protein. This particular GAP-related domain of the NF1 gene (NF1-GRD) stimulates ras GTPase and inactivates ras protein p21ras. Therefore, it has been suggested that the NF1 gene represents another tumor-suppressor gene. In the search for molecular markers of possible diagnostic relevance, childhood brain-tumor specimens of different histologic diagnoses were tested for mutations of the so-called FLR-exon within the NF1-GRD. This part of the NF1-GRD has been shown to be most crucial for the GAP-like function. Using a highly sensitive PCR-SSCP technique, we tested 51 tumor specimens were tested, but found no mutations. We conclude that inactivation of this putative tumor-suppressor gene by mutations does not play a significant role in tumorigenesis of childhood brain tumors. Next, we compared the splice variants of the NF1-GRD in 33 brain tumors and 8 extraneural embryonal tumors. Primitive neuroectodermal tumors (PNET) (n = 10) and one intracranial teratoma were the only tumors that predominantly expressed a splice pattern that can be observed in the immature developing brain. In contrast to other embryonal neuronal tumors, this NF1-GRD splicing pattern could not be modified in a newly established medulloblastoma cell line by retinoic acid treatment. Since this particular splice variant suppresses p21ras more effectively than other NF1-GRD transcripts, its predominant expression may interfere with the physiological signal transduction of p21ras during differentiation of neurons. There may be a neurofibromin-induced and p21ras-mediated differentiation pathway of neuronal stem cells that is blocked in PNET. Such an arrest of a p21ras-dependent differentiation pathway may explain the persistence of primitive pluripotent neuronal cells in PNET.

Alternative Splicing↗

ECK, a human EPH-related gene, maps to 1p36.1, a common region of alteration in human cancers.

Mouse eck, a member of the EPH gene family, has been mapped to mouse chromosome 4. The syntenic relationship between this chromosome and human chromosome 1 suggests that the human ECK gene maps to the distal short arm of human chromosome 1 (1p). Since this region is frequently deleted or altered in certain tumors of neuroectodermal origin, it is important to define the specific chromosomal localization of the human ECK gene. PCR screening of a rodent-human somatic cell hybrid panel by ECK-specific primers showed that ECK is indeed localized to human chromosome 1. Additional PCR screening of a regional screening panel for chromosome 1p indicated that ECK is localized to 1p36, distal to FUCA1. Furthermore, fluorescence in situ hybridization analysis with an ECK-specific P1 clone showed that ECK maps proximal to genetic marker D1S228. Taken together, the data suggest that ECK maps to 1p36.1, a region that is frequently deleted in neuroblastoma, melanoma, and other neuroectodermal tumors.

Animals↗

Ifosfamide in pediatric malignant solid tumors.

Ifosfamide/mesna was given to 97 patients who had malignant solid tumors diagnosed before they were 21 years of age. Patients received 1.6 g/m2 ifosfamide daily x 5, given i.v. over 15 min, followed by 400 mg/m2 i.v. mesna at 15 min and 4 and 6 h after ifosfamide. Responses were noted in patients with osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma and other soft-tissue sarcomas, rhabdoid tumor, neuroblastoma, Wilms' tumor, primitive neuroectodermal tumor, retinoblastoma, germ-cell tumors, and B-cell lymphoma. Toxicity included mild to moderate nausea and vomiting, transient, reversible myelosuppression, transient elevations of serum blood urea nitrogen (BUN) and creatinine and liver enzymes, infections, and self-limiting neurotoxicity characterized by changes in mental status, motor dysfunction, cranial nerve palsy, cerebellar dysfunction, and seizures. Neurotoxic symptoms were generally seen in patients who had previously received cisplatin. Ifosfamide is an important alkylating agent that should be combined with other agents in phase II and III trials. Alternate dose schedules should also be investigated.

Adolescent↗

Temporal lobe focal cortical dysplasia: MRI imaging using FLAIR shows lesions consistent with neoplasia.

Focal cortical dysplasia (FCD), a form of neuronal migration disorder, is a malformative lesion of the neocortex that occurs during development of the brain. It can cause partial and generalized epilepsy. Seizures occur at an early age and are often resistant to medication. Surgical resection has been found to be beneficial in these patients. Dual pathology, in the form of mesial temporal sclerosis, has been associated with FCD. At the Children's Hospital of Eastern Ontario, four patients with temporal lobe FCD have recently, been identified. This paper discusses how these children presented and how they were managed, with particular emphasis on their MRI findings and differential diagnoses. In three of the four patients neuroimaging studies showed lesions consistent with a neoplastic process because of the large volume and mass effect. Radiologically, FCD may mimic the MRI appearance of tumors, such as dysembryoplastic neuroepithelial tumors, primitive neuroectodermal tumors, gangliogliomas, oligodendrogliomas, and astrocytomas. These lesions are best visualized on fluid-attenuated inversion recovery (FLAIR) imaging, a technique that has recently become applicable in the clinical setting, as we help demonstrate in this series. With better MRI capability, milder forms of FCD and microdysplasia may be distinguished.

Brain Diseases↗

Postoperative chemotherapy and delayed radiation in children less than three years of age with malignant brain tumors.

BACKGROUND: Among patients with malignant brain tumors, infants and very young children have the worst prognosis and the most severe treatment-related neurotoxic effects. Therefore, in 1986, the Pediatric Oncology Group began a study in which postoperative chemotherapy was given in order to permit a delay in the delivery of radiation to the developing brain. METHODS: Children under 36 months of age with biopsy-proved malignant brain tumors were treated postoperatively with two 28-day cycles of cyclophosphamide plus vincristine, followed by one 28-day cycle of cisplatin plus etoposide. This sequence was repeated until the disease progressed or for two years in 132 children 24 months of age at diagnosis and for one year in 66 children 24 to 36 months of age at diagnosis. After this, the patients received radiation therapy. The response to the first two cycles of chemotherapy was measured in 102 patients with residual postoperative disease. RESULTS: The first two cycles of cyclophosphamide and vincristine produced complete or partial responses in 39 percent of the 102 patients who could be evaluated. The response rates were highest among patients with medulloblastomas, malignant gliomas, or ependymomas. Patients with brain-stem gliomas or embryonal tumors (primitive neuroectodermal tumors) had little or no response. The progression-free survival rate was 41 percent at one year for children who were 24 to 36 months old at diagnosis and 39 percent at two years for those under 24 months of age at diagnosis. Multivariate analysis identified embryonal tumors as a significant adverse prognostic feature (relative risk, 2.2; 95 percent confidence interval, 1.4 to 3.4) and complete resection as a favorable feature (relative risk, 0.33; 95 percent confidence interval, 0.20 to 0.54). Complete responses to chemotherapy were associated with a progression-free survival rate approaching that achieved with gross total resection. A comparison of cognitive evaluations obtained at base line and after one year of chemotherapy revealed no evidence of deterioration in cognitive function. CONCLUSIONS: Chemotherapy appears to be an effective primary postoperative treatment for many malignant brain tumors in young children. Disease control for one or two years in a large minority of patients permitted a delay in the delivery of radiation and, on the basis of preliminary results, a reduction in neurotoxicity. For patients who had undergone total surgical resection or who had a complete response to chemotherapy, the results are sufficiently encouraging to suggest that radiation therapy may not be needed in this subgroup of children after at least one year of chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

The role of electron microscopy in gynecological pathology.

Electron microscopy, as a diagnostic method, has been available to pathologists for about half a century. Its use in studying normal and abnormal gynecological tissues has been applied during the second half of that period, and many works on specific female genital topics have been published. Several of those subjects are worthy of citing in a review of the present type. Clear cell carcinoma has been revealed to be a mullerian, rather than a wolffian, derivative. Small cell carcinoma of the ovary with hypercalcemia is comprised of cells shown ultrastructurally to be epithelial, but unlike surface epithelial cells, germ cells, sex-cord cells, or neuroendocrine cells. Further electron microscopic studies provided evidence that these small cell tumors are not adult diffuse granulosa cell tumors, endometrioid stromal tumors, primitive neuroectodermal tumors, or numerous other primary and metastatic small cell tumors. Electron microscopy has also been useful in determining that not all signet-ring cell tumors of the ovary are stromal, and that there are multiple types of signet-ring (vacuolated) cells in ovarian tumors. Smooth muscle tumors are well known to have multiple light microscopic phenotypes, and electron microscopy has proven to be diagnostic in many of these cases, especially in epithelioid smooth muscle tumors. A number of other gynecological neoplasms that have been better defined by electron microscopic studies are described. Embryology and histogenesis are other areas of study in which electron microscopy has been a major contributor of new information at the subcellular level. Electron microscopy, solely or in harmony with clinical information, light microscopy, and immunohistochemistry, has been and is a valuable tool for the pathologist in the study of histogenesis and accurate diagnosis of gynecological lesions.

Adenocarcinoma, Clear Cell↗

Evaluation of the antitumor efficacy, pharmacokinetics, and pharmacodynamics of the histone deacetylase inhibitor depsipeptide in childhood cancer models in vivo.

PURPOSE: Histone acetyltransferases and histone deacetylases (HDAC) control the acetylation state of histones and other proteins regulating transcription and protein function. Several structurally diverse HDAC inhibitors have been developed as cancer therapeutic agents and in vitro have been shown to cause differentiation, cell cycle arrest, or apoptosis. Here, we have evaluated depsipeptide, a natural tetrapeptide HDAC inhibitor, against a panel of pediatric solid tumor models in vivo and evaluated pharmacokinetic and pharmacodynamic variables with tumor sensitivity. EXPERIMENTAL DESIGN: Depsipeptide was administered at the maximum tolerated dose (4.4 mg/kg administered every 7 days x 3 i.v. repeated q21d for a total of two cycles) to scid mice bearing 39 independently derived childhood tumors (9 brain tumors, 11 kidney cancers, 9 rhabdomyosarcomas, 3 neuroblastomas, and 7 osteosarcomas). Pharmacokinetic variables were determined, as were changes in histone and p53 acetylation, induction of p53 and p53 genotype, and alterations in Akt phosphorylation. RESULTS: Of 39 tumors evaluated, three showed objective tumor regressions [two brain tumors (primitive neuroectodermal tumor and atypical teratoid malignant rhabdoid tumor) and one Wilms' tumor]. Depsipeptide inhibited growth of many tumor lines but achieved stable disease (<25% increase in volume during treatment cycle 1) in only two tumor models (anaplastic astrocytoma, two rhabdomyosarcomas, and a Wilms' tumor). Pharmacokinetic analysis showed that the population estimated AUC(0-24) was 1,123 ng h/mL, similar to the exposure following 13 mg/m2 in ongoing phase I trials. Pharmacodynamic changes in histone acetylation (H2A, H2B, H3, and H4) in three depsipeptide-sensitive and three intrinsically resistant tumors followed a similar pattern; maximal increases in histone acetylation occurred at 8 hours and were elevated for up to 96 hours. In two sensitive tumor lines, IRS56 and BT27 (both wild-type p53) p53 increased in treated tumors being maximal at 8 hours and associated with induction of p21(cip1), whereas p53 was stable in tumors with mutant p53. Sensitivity to depsipeptide did not correlate with p53 genotype, p53 acetylation, cleaved poly(ADP-ribose) polymerase, or phosphorylation of Akt (Ser473). CONCLUSIONS: Our results show that depsipeptide inhibits its target in vivo causing increased histone acetylation; however, this does not correlate with drug sensitivity. The relatively low objective response rate [3 of 39 (8%) tumor lines showing greater than or equal to partial response and 4 (10%) stable disease] administered at dose levels that give clinically relevant drug exposures suggests that as a single agent depsipeptide may have limited clinical utility against pediatric solid tumors in a first-line setting.

Acetylation↗

Immunophenotypic characterization of infiltrating polynuclear and mononuclear cells in childhood brain tumors.

During a systematic cell surface antigen expression profile analysis of 76 primary childhood brain tumors (34 medulloblastomas/primitive neuroectodermal tumors and 42 astrocytomas), we employed the following library of monoclonal antibodies (MoABs): anti-Leu-2/a; anti-Leu-3/a; anti-Leu-M5; anti-Leu-11b; anti-HLA-A, -B, -C; anti-HLA-DR; anti-HLe-1 (leukocyte common antigen); and UJ 308. The MoABs identified the expression of various leukocyte-associated, lymphocyte cell line differentiated, cell surface antigens in childhood brain tumors. The antigens were detected with an indirect, biotin-streptavidin-conjugated alkaline phosphatase (AP) immunocytochemical technique. Leu-2/a+ cells comprise the significant CD8+ cytotoxic T-lymphocyte (CTL) population of the tumor-infiltrating lymphocytes. CTLs are major histocompatibility complex (MHC) class I restricted, tumor-associated antigen-specific, cytotoxic cells and were identified in 58 of 76 (76.32%) brain tumors. CTLs usually represented 1-10% of all cells, but in some cases 30-44% of the cells were CD8+. CD4+, MHC class II restricted helper lymphocytes, detected with MoAB anti-Leu-3/a, were present in 65 of 76 (85.53%) brain tumors. Usually 1-10% of the observed cells reacted with MoAB anti-Leu 3/a. Macrophages (Leu-M5 antigen-positive cells) were expressed in 74 of 76 (97.37%) brain tumors. Their number also represented 1-10% of all observed cells in the frozen brain tumor sections. All 76 (100%) brain tumors contained cells that reacted positively with MoABs anti-HLA-A, -B, -C and anti-HLA-DR, demonstrating a strong MHC class I restriction of the tumor cell population and an overall leukocyte antigen expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗

Diverse roles of insulin-like growth factors in pediatric solid tumors.

Insulin-like growth factors are abnormally expressed in some pediatric solid tumors. In addition, tumors that do not show significant alterations in pattern of expression are responsive to and may be dependent upon insulin-like growth factors for proliferation. These can be produced by the tumor cells (autocrine), surrounding stromal cells (paracrine), or at a distance (endocrine). Insulin-like growth factor-II plays a role in Wilm's tumor, neuroblastoma, and rhabdomyosarcoma, either as a proliferation factor, a motility factor, or both. Insulin-like growth factor-I may regulate osteosarcoma and the Ewing's family of tumors (primitive neuroectodermal tumors). Understanding the biology of these growth factors and their receptors can lead to new therapeutic approaches.

Adult↗

Olfactory neuroblastoma and other round cell lesions of the sinonasal region.

Sixty-nine round cell lesions of the sinonasal region (22 olfactory neuroblastomas [ONBs], 17 malignant lymphomas, nine Ewing's sarcomas [ES], nine rhabdomyosarcomas, three sinonasal undifferentiated carcinomas, five malignant melanomas, and four pituitary adenomas) were studied in an attempt to define the differential diagnostic capabilities of antibody to MIC2 and bcl-2 in paraffin-embedded tissue in the distinction of these lesions. In addition, antibody to p53 was applied in each case to define the incidence of p53 positivity among these various tumor types. Each of the ES cases was MIC2 positive; each of the other cases was MIC2 negative. Positivity for bcl-2 was confined to two cases, one of them a malignant lymphoma (85% of cells positive) and one an ONB (5% of cells positive). Small numbers of scattered p53-positive cells appeared in the majority of cases studied, without regard for the specific tumor type; only a single case, a malignant lymphoma, showed a majority (approximately 90%) of p53-positive cells. These results indicate that the MIC2 antibody is a useful method by which to distinguish ES from a variety of other round cell lesions that may be encountered in the sinonasal region. The practical applications of antibody to bcl-2 and p53 seem to be much more limited; by contrast, neither bcl-2 positive cells nor abundant p53 cells identified by immunohistochemical analysis seemed to be frequent findings in any of the tumor types studied. Although ONBs have been included with the peripheral primitive neuroectodermal tumors for classification purposes, these tumors diverge from the ES/primitive neuroectodermal tumor family in that they do not seem to share either the MIC2 positivity or the t(11;22) chromosomal translocation that typify the ES/primitive neuroectodermal tumor family of lesions. Although bcl-2 positivity has been associated with a light microscopic finding of an unfavorable histologic pattern in retroperitoneal neuroblastomas, it does not seem that bcl-2 positivity in ONB will select for a clinically distinctive subset of patients.

12E7 Antigen↗

Expression of human fetal brain antigens by human tumors of neuroectodermal origin as defined by monoclonal antibodies.

The antigenic relationships between human tumors of neuroectodermal origin and fetal brain were investigated by the production of hybridoma antibodies derived from a fusion of P3-NS1/1-Ag 4-1 (NS1) myeloma cells with splenocytes from a mouse multiply immunized with an homogenate of second-trimester human fetal brain tissue. Two monoclonal antibodies (MAs), 4D2cl 6 and 7H10cl 4, were studied in detail by cell surface radioimmunoassay (CS-RIA), quantitative absorption, indirect immunofluorescence, and peroxidase-anti-peroxidase (PAP) immunohistology. MA 4D2cl 6 binds to 5 of 14 glioblastoma (GBM) cell lines, 1 of 2 melanoma cell lines, 1 of 3 neuroblastoma cell lines, and 1 of 5 fetal fibroblast lines by CS-RIA and to 13 of 13 GBM, 1 neuroblastoma, and fetal brain, liver, spleen, and adult spleen unfixed frozen tissue by PAP analysis. MA 7H10cl 4 binds to 13 of 14 GBM, 1 of 3 neuroblastoma, and 1 medulloblastoma cell line(s) by CS-RIA analysis and to 13 of 13 GBM, 1 neuroblastoma, fetal brain, liver, spleen, thymus, and adult spleen by PAP analysis. Control non-central nervous system tumors and normal adult tissue, including brain, were unreactive with both MAs by CS-RIA, PAP, and absorption analysis. Tissue distribution and localization analyses established that MAs 4D2cl 6 and 7H10cl 4 recognize specificities of shared fetal-neuroectodermal-lymphoid distribution which are operationally specific within the adult central nervous system and which are not related to previously described oncofetal or onconeural antigens.

Antibodies, Monoclonal↗

Resistance to TRAIL-induced apoptosis in primitive neuroectodermal brain tumor cells correlates with a loss of caspase-8 expression.

TNF-related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in adult malignant glioma and various other human solid tumor models but not in normal tissues. To characterize the TRAIL death pathway in childhood primitive neuroectodermal brain tumor (PNET), 8 human PNET cell lines were tested for TRAIL-induced apoptosis. TRAIL-sensitivity of the PNET cell lines was correlated with mRNA expression levels of TRAIL, its agonistic (TRAIL-R1, TRAIL-R2) and antagonistic (TRAIL-R3, TRAIL-R4) receptors, cellular FLICE-like inhibitory protein (cFLIP), caspase-3 and caspase-8. Three of 8 PNET cell lines tested were susceptible to TRAIL-induced apoptosis. Sensitivity to TRAIL-induced apoptosis did not correlate with mRNA expression of TRAIL receptors or cFLIP. However, all TRAIL-sensitive PNET cell lines expressed caspase-8 mRNA and protein, while none of the five TRAIL-resistant PNET cell lines expressed caspase-8 protein. Treatment with the methyltransferase inhibitor 5-aza-2'-deoxycytidine restored mRNA expression of caspase-8 and TRAIL-sensitivity in formerly TRAIL-resistant PNET cells, suggesting that gene methylation inhibits caspase-8 transcription in these cells. We conclude, that loss of caspase-8 mRNA is an important mechanism of TRAIL-resistance in PNET cells. Treatment with recombinant soluble TRAIL, possibly in combination with methyltransferase inhibitors, represents a promising therapeutic approach for PNET that deserves further investigation.

Adult↗

Glioneuronal tumors of the central nervous system.

Advances in the immunohistochemical detection of neuron-specific and neuronal-associated antigens have resulted in the discovery of neuronal elements in certain primary human brain tumors. The results have been not only to expand what neuropathologists commonly recognize as gangliogliomas, including the tumors now known as glioneurocytic tumor with neuropil rosettes and papillary ganglioneuroma, but also to expand the spectrum of tumor types to now include tumors such as central neurocytoma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile ganglioglioma. These discoveries have helped us to better understand the biology of these tumors and to refine our classification of them. Distinctions among these tumors include sites of predilection, such as the temporal lobe with the dysembryoplastic neuroepithelial tumors, and a spectrum of clinical aggressiveness that spans indolent "quasi-hamartomatous" lesions, such as the dysembryoplastic neuroepithelial tumor, to high-grade, highly aggressive tumors, such as the supratentorial primitive neuroectodermal tumor (World Health Organization Grade IV). Many of these tumors also commonly exhibit a glial component, as determined by both their histologic appearance and their immunoreactivity for glial fibrillary acidic protein. This review covers these recently described lesions, including the desmoplastic infantile ganglioglioma, the dysembryoplastic neuroepithelial tumor, the papillary glioneuronal tumor, the glioneuronal tumor with neuropil rosettes, and the mixed glioblastoma-cerebral neuroblastoma (supratentorial primitive neuroectodermal tumor), as well as the known tumors, ganglioglioma, medulloepithelioma, and medulloblastoma. For pathologists confronted by this growing array of tumors and subtypes, it is appropriate to focus on them and understand the differential diagnosis to be considered when confronted by them.

Central Nervous System Neoplasms↗

Expression of three viral oncogenes (v-sis, v-myc, v-fos) in primary human brain tumors of neuroectodermal origin.

We determined which viral oncogenes (v-sis, v-myc, and v-fos) were expressed in five primary human brain tumors of neuroectodermal origin (two glioblastomas multiforme, one medulloblastoma, one cystic cerebellar astrocytoma, and one ganglioglioma) and which of these oncogenes is correlated with malignancy. Using the dot hybridization technique, we determined the relative amounts of mRNA coded by these genes using the same nitrocellulose filter. The v-myc probe showed a 4- to 12-fold greater hybridization to the mRNA from two glioblastomas and the medulloblastoma (malignant group) than the mRNA from the cystic cerebellar astrocytoma or the ganglioglioma (benign group). In contrast, RNA hybridizing to v-sis and v-fos were accumulated to a greater extent in the benign tumors. These data suggest that the amount of myc expression may be correlated with the degree of malignancy of brain tumors of neuroectodermal origin.

Brain Neoplasms↗

Activation of trkA induces differentiation and inhibits the growth of JK-GMS Askin tumor cells.

Peripheral primitive neuroectodermal tumor (PNET) and Ewing's sarcoma (ES) constitute a unique group of small round cell tumors in childhood and young adults that are characterized by the same chromosomal translocation t(11;22)(q24;q12). Recently, the expression of neurotrophin receptors has been found in various human tumors including PNET/ES, but the functional significance of these receptor expressions has not been documented in PNET/ES. In the present study, we investigated the biologic effects of trkA neurotrophin receptor activation by nerve growth factor (NGF) in a newly established Askin tumor cell line, JK-GMS, which constitutively expresses a high level of trkA. The activation of trkA induced differentiation and inhibited the growth of JK-GMS cells, which was characteristically associated with down-regulation of c-myc and N-myc mRNA expression. NGF did not exert significant changes in two different PNET/ES cell lines, CADO-ES1 and RD-ES, which did not express detectable levels of trkA. The biologic effects mediated by NGF were abrogated by treatment of the cells with K-252a, and the treatment with brain-derived neurotrophic factor did not affect the biologic behavior of JK-GMS cells, indicating that the effects are trkA specific. The results observed were quite similar to those of neuroblastoma cells, another childhood tumor of neural crest origin. Overall findings strongly suggest that the trkA-mediated signaling pathway plays a crucial role in controlling the basic biologic properties of JK-GMS cells.

Adolescent↗

Melanotic neuroectodermal neurocranial tumor of infancy of extra-intra-and subdural right temporal location: CT examination, surgical treatment, literature review.

A melanotic neuroectodermal neurocranial tumor of infancy of extra-intra-subdural right temporal location, examined by CT and successfully operated in a 33-month-old boy is reported in context with the literature. Out of 30 cases (including our case) of melanotic neuroectodermal neurocranial and intracranial tumors (MNNIT) 18 were located in the neurocranium (MNNT) and 12 intracranially, i.e. in the brain and cerebellum (MNIT). 23 tumors were located medially (11 at the anterior fontanel, one at the posterior fontanel, one in the 3rd ventricle, one in the sella turcica, one in the pineal region, 8 in the cerebellar vermis) and 7 laterally (five involved the temporal bone, one of which with intracranial propagation (our case), one in the temporal lobe of the brain, one in the skull posterior to the mastoid process). Twenty-eight cases were children (16 boys, 8 girls, four not stated), two adults. The location is important in respect to biology and surgery: MNNIT can be grouped as to its relation to the arachnoid barrier layer into malignant and benign. MNIT localised medially subarachnoidally are malignant. MNNT of small dimensions localised medially and laterally extraarachnoidally are benign. MNNT of extreme dimensions localised medially extra-intradurally are also benign, but difficult to treat. In the MNNT when diagnosed early and operated radically, the mortality can be lowered. Our case, presented on CT (1978) as first case of combined extra-intra-subdural location, represents the 173rd MNT and the 18th related to neurocranium.

Brain Neoplasms↗

Primary cutaneous Ewing's sarcoma: immunophenotypic and molecular cytogenetic evaluation of five cases.

Cutaneous small blue cell tumors are relatively uncommon and include primary lesions of either adnexal or neuroendocrine differentiation, as well as metastatic disease. Extraosseous Ewing's sarcoma/malignant primitive neuroectodermal tumor (MPNET) rarely may occur as a primary, superficially based neoplasm in children and young adults. We describe a series of five cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor occurring as a primary cutaneous malignancy supported diagnostically both by immunohistochemical stains and fluorescence in situ hybridization (FISH). All five cases occurred as a solitary dermal nodule and were located in the lower extremities (3 cases), the axilla (1 case), and the flank (1 case). Three of the cases were clinically polypoid. Four of the five patients were female, and age at presentation ranged form 8 to 50 years of age (median, 18 years). All five tumors consisted of nodular proliferations of monomorphous, small blue cells with round, vesicular nuclei, and scant to moderate cytoplasm that were uniformly immunoreactive for the CD99 cell surface glycoprotein in a characteristic membranous pattern. Fluorescence in situ hybridization analysis of paraffin-embedded tissue revealed that three of four tumors were positive for a chromosomal translocation involving the EWS locus at 22q12, seen in more than 90% of cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor. One case was not analyzable. All five patients were treated using local excision, and two patients additionally received postoperative chemotherapy and radiotherapy. Clinical follow-up is available in three cases (median duration, 33 months) and to date none has shown evidence of either local recurrence or metastasis. Because similar cases reported in the literature have likewise had favorable clinical courses after excision, primary cutaneous Ewing's sarcoma/malignant primitive neuroectodermal tumor may represent a clinically favorable subset of this otherwise highly aggressive neoplasm.

Adolescent↗

Neurotrophin receptor TrkC predicts good clinical outcome in medulloblastoma and other primitive neuroectodermal brain tumors.

BACKGROUND: Neurotrophins and their cognate receptors TrkA, TrkB and TrkC regulate proliferation, differentiation and death of neuronal progenitor cells and may be implicated in the progression of medulloblastoma and other primitive neuroectodermal brain tumors (PNET). These common childhood brain tumors are composed of morphologically undifferentiated cells that have important similarities to neuroectodermal progenitor cells of the developing CNS. PATIENTS AND METHODS: To identify biologic prognostic factors in childhood PNET we determined expression levels of TrkC mRNA in tumor samples from 87 PNET patients by in situ hybridization. Comparison of TrkC mRNA expression levels with clinical variables was performed using univariate and multivariable Cox regression analysis. RESULTS: Cox regression analysis revealed that children with tumors expressing no or little TrkC mRNA had a 4.8-fold (p < 0.00005) greater risk of death than children with tumors with high TrkC mRNA expression. This hazard ratio remained consistent after adjusting for clinical variables. Five-year survival was 89% for patients with PNETs expressing high levels of TrkC mRNA and 47% for patients with PNETs expressing little or no levels of TrkC mRNA (log rank; p < 0.00005). CONCLUSIONS: The TrkC neurotrophin receptor appears to be a powerful independent prognostic factor in PNET and may have a role in patient assignment to risk-based treatment strategies.

Adolescent↗