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PubMedDate not supplied

Improvement of the methylation specific PCR technical conditions for the detection of p16 promoter hypermethylation in small amounts of tumor DNA.

Methylation specific PCR (MSP) is a technique that enables the detection of hypermethylation at a CpG island. The objective of this study is the introduction of small modifications to the MSP technique to make it more suitable for the study of promoter hypermethylation at tumor suppressor genes whenever there is a shortage of material available for study. This commonly happens in the case of using archival material from the Pathology departments. Tumor DNA was extracted from a collection of 40 fresh-frozen soft tissue sarcomas and 19 paraffin-embedded PNETs (primitive neuroectodermal tumors). The MSP technique was performed to detect hypermethylation at the p16 promoter. Also, blood genomic DNA was mixed with herry sperm genomic DNA as a carrier, in nine different combinations, in order to test for the best conditions that could produce MSP bands even when low amounts of genomic tumor DNA is available for study. We demonstrate the benefit of using herry sperm carrier DNA up to 10 microg together with small quantities of tumor DNA. This result will facilitate the incorporation of paraffin-embedded samples for study of promoter hypermethylation at tumor suppressor genes. Other technical conditions for the MSP technique are also studied.

Brain Neoplasms↗
PubMed1985

Ependymoblastoma associated with prenatal exposure to diphenylhydantoin and methylphenobarbitone.

Ependymoblastoma developed in a 28-month-old girl whose epileptic mother took diphenylhydantoin and methylphenobarbitone throughout pregnancy. The child was also shown to be a genetic carrier for ornithine transcarbamylase deficiency, an x-linked inborn error of urea cycle metabolism. The possibility of transplacental carcinogenesis should be considered, as other juvenile embryonic tumors such as neuroblastoma, melanotic neuroectodermal tumor, and mesenchymoma have been reported in offspring after diphenylhydantoin use by the mother during pregnancy.

Brain Neoplasms↗
PubMed1995

cDNA cloning, molecular characterization, and chromosomal localization of NET(EPHT2), a human EPH-related receptor protein-tyrosine kinase gene preferentially expressed in brain.

By screening a human fetal brain cDNA expression library using a monoclonal anti-phosphotyrosine antibody, we have isolated a cDNA clone encoding a receptor type protein-tyrosine kinase belonging to the EPH family, NET (neuronally expressed EPH-related tyrosine kinase). NET shows 87% homology in nucleotide sequence and 99% homology in the deduced amino acid sequence to rat elk, suggesting that NET is the human homologue of elk. The NET gene is mapped to human chromosome 3q21-q23 by PCR screening of a human-rodent somatic cell hybrid panel and by fluorescence in situ hybridization. Examination of NET mRNA expression in several human tissues has shown that the NET gene is expressed preferentially in brain as a 5-kb transcript. Steady-state levels of NET mRNA in human brain are greater in the midterm fetus than in the adult. Lower levels of NET mRNA are found in fetal kidney and adult skeletal muscle. The expression pattern of NET mRNA thus differs from that of elk, suggesting that these two gene products may perform distinct roles in human and rat. NET transcripts are detected in human NTera-2 teratocarcinoma cells after retinoic acid-induced neuronal differentiation. Several human tumor cell lines derived from neuroectoderm including primitive neuroectodermal tumor, small cell lung carcinoma, and neuroblastoma also express NET transcripts. Since the NET mRNA expression in human brain is developmentally regulated and is induced during neuronal differentiation, NET potentially plays important roles in human neurogenesis.

Adult↗
PubMed1992

Temporal trends among childhood brain tumor biopsies. The Childhood Brain Tumor Consortium.

We sought temporal trends in the demographic, clinical, histologic feature, diagnostic class, and quality of life data over the interval 1930-1979 in the Childhood Brain Tumor Consortium database. The proportion of children younger than eight years old declined from 72% to 55% and the proportion of those older than ten more than doubled from 12% to 27%. The relative frequency of tumors in the supratentorial compartment increased significantly, while infratentorial tumors decreased. We found significant declines in supratentorial ependymomas and pilocytic astrocytomas. Similarly, some infratentorial tumors, especially ependymomas, decreased and brain stem tumors increased. Infratentorial medulloblastoma (primitive neuroectodermal tumor) increased significantly. Some individual histologic features which are markers of anaplasia increased in frequency in both supratentorial and infratentorial tumors. There was a significant increase in biopsies that contained nonneoplastic neural tissue in addition to tumor for both compartments and among supratentorial tumors there was a marked increase in the proportion of cases containing an indistinct neural tissue boundary. The probability of postoperative death declined, but the probability of survival five or ten years after surgery did not improve significantly for children who had tumors in either compartment. Among children who survived five years after the initial craniotomy, the proportion who had significant long term deficits increased. Most of this increase occurred in the last decade (1970-79). In this decade, the proportion of children for whom no deficits were reported five years following operation was 4% if they had a supratentorial tumor and 27% if they had an infratentorial tumor. The proportions of children alive five years following first surgery who had arachnoidal metastases increased significantly for infratentorial tumors.

Adolescent↗
PubMed1989

Melanotic paraganglioma of the orbit: a case report.

A paraganglioma of the orbit in a 21-year-old woman is presented, containing oculo-cutaneous melanin in many tumor cells, occasionally adjacent to neurosecretory granules, and in macrophages. This tumor expands the list of neuroectodermal tumors with potential melaninization.

Adult↗
PubMed2002

Aberrant immunohistochemical expression in nonrhabdomyosarcoma soft tissue sarcomas of infancy: retrospective review of clinical material.

Malignant soft tissue tumors other than rhabdomyosarcoma (RMS) are uncommon in infancy, representing approximately 5% of pediatric sarcomas. The pathological categorization of non-RMS soft tissue malignancies from these young patients is complicated by variation in both morphologic and immunohistochemical features. A search covering an 11-year period identified 19 patients presenting at birth or in infancy with a clinical or referral diagnosis of soft tissue sarcoma. After histologic and immunohistochemical review, nine of these tumors were classified as primitive neuroectodermal tumor (PNET), three as infantile hemangiopericytoma (HPC), two as infantile fibrosarcoma (FS), and five as undifferentiated sarcoma. Those identified as undifferentiated sarcomas showed an atypical spindle and ovoid cell morphology, with cellular pleomorphism and high mitotic rate, but lacking the fascicular growth pattern of classic infantile fibrosarcoma. Immunohistochemical staining in this group showed variable weak positivity for a range of markers (desmin, smooth muscle actin, Myo-D1, PGP, NSE, S100, CO56, cytokeratin, and CD99), and did not fit readily into any distinct diagnostic category. In this series, tumors classified as soft tissue PNETs had a poor prognosis despite aggressive treatment. However, once RMS, PNET, and other rare specific lesions are excluded, the remaining undifferentiated sarcomas, despite their unusual morphology and immunohistochemistry, appear to behave in a similar favorable manner to infantile fibrosarcoma.

Humans↗
PubMed1992

Identification of a novel tyrosine kinase receptor-like molecule in neuroblastomas.

Growth factor receptors are important determinants of both normal and abnormal cell growth. We have now used degenerate primers designed from conserved tyrosine kinase domains to identify and clone a novel receptor-like molecule (designated Nbtk-1) from a NB41 mouse neuroblastoma cell line. Nbtk-1 is related to the met proto-oncogene family of tyrosine kinase receptors. Transcripts of approximately 2.1 and 2.6 kb have been found in mouse cell lines and one transcript of approximately 3 kb in human cell lines and in a wide range of primary human tumors, such as neuroblastomas, primitive neuroectodermal tumors (PNETs), Wilms' tumors, and melanomas and in the corresponding normal human tissues. These observations suggest that Nbtk-1 may have important roles in normal and tumor cell growth.

3T3 Cells↗
PubMed1988

Ultrastructural findings in transplanted experimental brain tumors and their significance for the cytogenesis of such tumors.

Tumors induced by transplacental action in the spinal cord of rats were transplanted into the brains of the same rat strain. They were followed up by electron microscopy during the first ten passages. Three architectural features were detected: First pure tumor parts, second myelin breakdown and phagocytosis, and third the resulting accumulation of resting macrophages. Architecture two and three were interpreted as result of considerable phagocytotic activity of tumor cells localized within the white substance of the brain and spinal cord. Only architecture one was considered to represent proper tumor. Since this was low differentiated and partial astrocytic differentiation only occurred around vessels to remarkable extent, the thesis is put forward that these transplacentally induced tumors correspond to human primitive neuroectodermal tumors.

Animals↗
PubMedDate not supplied

Immunocytochemical detection of leukocyte-associated and apoptosis-related antigen expression in childhood brain tumors.

During systematic cell-surface antigen expression profile analyses of 76 primary childhood brain tumors [34 medulloblastomas (MED)/primitive neuroectodermal tumors (PNETs) and 42 astrocytomas (ASTR)], a library of monoclonal antibodies (MoABs) directed against various leukocyte-associated, lymphocyte cell-line differentiation antigens in childhood brain tumors was utilized. The antigens were detected employing an indirect, biotin-streptavidin conjugated alkaline phosphatase (AP) immunocytochemical technique. Major histocompatibility complex (MHC) class I restricted, tumor-associated antigen (TAA) specific, CD8(+) cytotoxic T lymphocytes (CTL) were identified in 58/76 (76.32%) brain tumors, and 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 were present in 65/76 (85.53%) brain tumors, and accounted for 1-10% of the observed cells. Macrophages were present in 74/76 (97.37%) brain tumors, and their number also represented 1-10% of all observed cells in the brain tumor frozen sections. Leukocyte common antigen (LCA) expression was detected in all 76 (100%) brain tumors studied. MoAB UJ 308 detected the presence of premyelocytes and mature granulocytes in 60/76 (78.95%) brain tumors. Natural killer (NK) cells were not defined in the observed brain tumors. The great majority of childhood glial tumors, particularly ASTRs express Fas (APO-1/CD95) receptor whereas normal cells in the central nervous system (CNS) do not. FasR is a transmembrane glycoprotein which belongs to the nerve growth factor/tumor necrosis factor (NGF/TNF) receptor superfamily. As part of our screening, the 42 childhood ASTRs were also investigated for expression of CD95. We detected strong expression (strong intensity of staining, number of stained cells 50-100%) of FasR, employing formalin fixed, paraffin-wax embedded tissue slides. Brain tumors and melanomas have been shown to produce their autocrine FasL, and are even capable of switching CD95-related signal transduction from the PCD pathway to a proliferative pathway. In view of our results, we conclude that: (1) the tumor infiltrating leukocytes in MEDs/PNETs and ASTRs represent a very diverse population and are present in a great majority of the cases studied; (2) the strong expression of FasR in ASTRs provides a manner in which T lymphocytes may exert their anti-tumor effects, but may also represent yet another way that tumors may evade the immune response; and (3) further observations of the expression of various antigens involved in juxtacrine, in situ growth control are necessary for the refinement of cellular immunotherapeutical approaches in the treatment of human malignancies.

Antigens, Surface↗
PubMed1997

Neuropathology of pediatric brain tumors.

Pediatric central nervous system neoplasms include a spectrum of both glial and nonglial tumors that differ significantly in location and biological behavior from those of adults. Brain tumors in infants and children most often arise from central neuroepithelial tissue, whereas a significant number of adult tumors arise from central nervous system coverings (e.g., meningioma), adjacent tissue (e.g., pituitary adenoma), or metastases. Most adult brain tumors are supratentorial malignant gliomas, whereas the most common malignant pediatric brain tumor is the cerebellar primitive neuroectodermal tumor (medulloblastoma). This article reviews neuropathological characteristics of the more common pediatric brain tumors. Entities, such as the brainstem glioma, and less common neoplasms like the desmoplastic infantile ganglioglioma and the central nervous system atypical teratoid/rhabdoid tumor are reviewed because they occur almost exclusively in children. Known cytogenetic and molecular characteristics of childhood brain tumors are also reviewed.

Brain Neoplasms↗
PubMed1987

Expression of p21ras in normal and malignant human tissues: lack of association with proliferation and malignancy.

Proteins encoded by cellular ras oncogenes (p21ras) are expressed in a wide variety of malignant tumors, including carcinomas, lymphomas, and neuroectodermal tumors. The function of p21ras in these tumors and the distribution and role of p21ras in corresponding normal tissues are unclear. This immunohistochemical study examined the relationship between p21ras expression and malignant transformation, cellular differentiation, and proliferative activity in vivo. p21ras was found to be widely expressed in normal tissues, but within those tissues expression was often sharply restricted to cells at specific stages of differentiation; terminally differentiated cells generally showed stronger reactivity with antibodies to p21ras than did rapidly proliferating cells. Fetal and adult tissues had corresponding patterns of p21ras expression, and the distribution of p21ras in neoplasms paralleled the pattern in normal tissue from which they were derived. Thus, p21ras seems to play a role in many fully differentiated cell types, and levels of p21ras expression do not correlate with proliferative activity in normal cell or, in contrast to past reports, with the transformed phenotype.

Adult↗
PubMed2000

Familial posterior fossa brain tumors of infancy secondary to germline mutation of the hSNF5 gene.

We have identified a family afflicted over multiple generations with posterior fossa tumors of infancy, including central nervous system (CNS) malignant rhabdoid tumor (a subset of primitive neuroectodermal tumors, or PNET) and choroid plexus carcinoma. Various hereditary tumor syndromes, including Li-Fraumeni syndrome, Gorlin syndrome, and Turcot syndrome, have been linked to increased risk of developing CNS PNETs and choroid plexus tumors. Malignant rhabdoid tumors of the CNS and kidney show loss of heterozygosity at chromosome 22q11. The hSNF5 gene on chromosome 22q11 has recently been identified as a candidate tumor-suppressor gene in sporadic CNS and renal malignant rhabdoid tumors. We describe a family in which both affected and some unaffected family members were found to have a germline splice-site mutation of the hSNF5 gene, leading to exclusion of exon 7 from the mature cDNA and a subsequent frameshift. Tumor tissue shows loss of the wild-type hSNF5 allele, in keeping with a tumor-suppressor gene. These findings suggest that germline mutations in hSNF5 are associated with a novel autosomal dominant syndrome with incomplete penetrance that predisposes to malignant posterior fossa brain tumors in infancy.

Age of Onset↗
PubMed1995

Molecular characterization and chromosomal localization of DRT (EPHT3): a developmentally regulated human protein-tyrosine kinase gene of the EPH family.

By screening a human fetal brain cDNA expression library using a monoclonal antiphosphotyrosine antibody and by 5' RACE procedures, we have isolated overlapping cDNAs encoding a receptor-type tyrosine kinase belonging to the EPH family, DRT (Developmentally Regulated EPH-related Tyrosine kinase gene). The DRT gene is expressed in three different size transcripts (i.e. 4, 5 and 11 kb). DRT transcripts are expressed in human brain and several other tissues, including heart, lung, kidney, placenta, pancreas, liver and skeletal muscle, but the 11 kb DRT transcript is preferentially expressed in fetal brain. Steady-state levels of DRT mRNA in several tissues, including brain, heart, lung and kidney, are greater in the midterm fetus than those in the adult. DRT transcripts are detectable at low levels in a human teratocarcinoma cell line (NTera-2), but its expression is greatly increased after the NTera-2 cells are induced to become postmitotic neurons (NTera-2N) by retinoic acid treatment. These data suggest that DRT plays a part in human neurogenesis. A large number of tumor cell lines derived from neuroectoderm express DRT transcripts, including 12 neuroblastomas, two medulloblastomas, one primitive neuroectodermal tumor and six small cell lung carcinomas (SCLC). Interestingly, several neuroblastoma cell lines with 1p deletion and one SCLC cell line express DRT transcripts of aberrant size (i.e. 3, 6 and 8 kb) in addition to those found in normal tissues. We mapped the DRT gene to human chromosome 1p35-1p36.1 by PCR screening of human-rodent somatic cell hybrid panels and by fluorescence in situ hybridization. As the distal end of chromosome 1p is often deleted in neuroblastomas and altered in some cases in SCLCs, these chromosomal abnormalities may have resulted in the generation of aberrant size transcripts. Thus, the DRT gene may play a part in neuroblastoma and SCLC tumorigenesis.

Amino Acid Sequence↗
PubMed1997

Clinical aspects of brain tumor.

New approaches to treating patients with malignant brain tumors use advanced magnetic resonance and positron imaging. Clinical protocols to treat oligodendroglial-containing tumors, brain lymphoma or primitive neuroectodermal tumor make use of systemic administration of drugs before irradiation. Chemotherapy directed into tumor is provided for recurrent glioblastoma as is reoperation and the use of stereotactic radiosurgical boosts.

Animals↗
PubMedDate not supplied

Phase II trial of pyrazoloacridine in children with solid tumors: a Pediatric Oncology Group phase II study.

PURPOSE: Pyrazoloacridine (PZA), a rationally synthesized deoxyribonucleic acid (DNA) binding agent that preferentially inhibits ribonucleic acid rather than DNA synthesis, is active against hypoxic and noncycling tumor cells and has greater in vitro activity against a broad range of human solid tumor lines than against the L1210 murine leukemia line. The Pediatric Oncology Group conducted a phase II study to determine the activity of PZA administered as a 3-hour infusion. PATIENTS AND METHODS: The activity of PZA was evaluated in patients with a variety of childhood solid tumors including rhabdomyosarcoma, Ewing sarcoma/peripheral neuroectodermal tumor, neuroblastoma, osteogenic sarcoma, Wilms tumor, or other solid tumors (excluding brain tumors). In addition to a standard three-stage design to test the drug's activity in each tumor type, a global stopping rule was used such that if no complete or partial responses (CR or PR) occurred in the first 35 patients (pooled across all strata except "other"), the study would be closed. RESULTS: A total of 47 patients were entered into the study. Myelosuppression was the primary toxicity. Severe nonhematologic toxicity was uncommon. Only one patient exhibited grade 3 neurologic toxicity (anxiety). No CRs or PRs were observed. CONCLUSION: Use of the global stopping criterion permitted early identification of lack of activity of PZA against childhood solid tumors.

Acridines↗
PubMed2004

Application of stem cell transplant for brain tumors.

Brain tumors are the second most common malignancy in children and the most common solid tumor. The majority of children are treated with surgery alone or in combination with radiation and/or chemotherapy. Recently investigators have used high dose chemotherapy with autologous stem cell rescue (ASCR) in patients with malignant brain tumors. This approach has been most successful in chemosensitive tumors including medulloblastoma, supratentorial primitive neuroectodermal tumors (SPNET) and central nervous system germ cell tumors (CNS GCT). In addition, the use of high dose chemotherapy has enabled the reduction and in many cases elimination of radiation therapy to very young children. To date there have been no prospective randomized studies comparing high dose chemotherapy and ASCR with conventional therapy. Radiation therapy is often not an option for patients with recurrent disease and conventional dose chemotherapy rarely if ever results in long-term survival. Unfortunately, the majority of studies using conventional therapy in order to delay irradiation in young children newly diagnosed with malignant brain tumors have been unsuccessful. Although the numbers are small, preliminary data suggest that not only is survival but also quality of life is superior with the use of high dose chemotherapy. Future studies will most likely include the use of new agents as part of the cytoreduction. In addition, through the use of peripheral blood stem cells and improvements in supportive care, multiple courses of high dose chemotherapy can be administered. High dose chemotherapy with ASCR is a foundation upon which many different types of therapies can be built. Several possibilities include the use of anti-angiogenesis agents, monoclonal antibodies and biologic response modifiers.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Cervicothoracic lesions in infants and children.

Cervicothoracic lesions are not uncommon in children. All cervicothoracic lesions except superficial lesions extend from the neck to the thorax through the thoracic inlet. Evaluation of this area involves multiple imaging modalities: plain radiography, ultrasonography, nuclear medicine, computed tomography, and magnetic resonance (MR) imaging. However, MR imaging is the method of choice for assessing the full extents of cervicothoracic lesions and their relationships to neurovascular structures. Cervicothoracic lesions can be classified as congenital lesions, inflammatory lesions, benign tumors, malignant tumors, and traumatic lesions. Lymphangioma is the most common cervicothoracic mass in children; other congenital lesions include hemangioma, thymic cyst, and vascular anomalies. Inflammatory adenopathy reactive to tuberculosis, mononucleosis, tularemia, cat-scratch fever, infection with human immunodeficiency virus, or other upper respiratory tract infections can manifest as cervicothoracic lesions; tuberculous abscesses and abscesses of other origins can also be seen. Lipoma, lipoblastoma, aggressive fibromatosis, and nerve sheath tumors (either isolated lesions or those associated with neurofibromatosis) can also occur as cervicothoracic masses. Malignant cervicothoracic tumors include lymphoma, thyroid carcinoma, neuroblastoma, and chest wall tumors (rhabdomyosarcoma, Ewing sarcoma, and neuroectodermal tumor). Traumatic cervicothoracic lesions include pneumomediastinum of traumatic origin, traumatic pharyngeal pseudodiverticulum, esophageal foreign-body granuloma, and cervicothoracic hematoma.

Adolescent↗