Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Neuroectodermal Tumors, Primitive”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed1991

Immunohistochemical study of childhood rhabdomyosarcomas and related neoplasms. Results of an Intergroup Rhabdomyosarcoma study project.

The authors assessed a panel of immunohistochemical stains against 109 pediatric solid tumors, primarily rhabdomyosarcomas, under the auspices of the Intergroup Rhabdomyosarcoma Study. Fresh tumor tissue received from participating organizations was divided into portions that were either frozen or fixed in formalin, alcohol, or B5. Immunostaining was performed by the avidin-biotin complex method using monoclonal antibodies to desmin, neurofilaments, vimentin, cytokeratin, and leukocyte common antigen on cryostat sections. Tissue was also embedded in paraffin and stained with antimuscle-specific actin (MSA) and polyclonal antibodies to desmin, creatine kinase M subunit (CKM), myoglobin, and neuron-specific enolase (NSE). Antidesmin staining of cryostat sections was the most sensitive indicator of rhabdomyosarcoma (58 of 62 specimens positive). Results with this reagent in alcohol-fixed and formalin-fixed tissue were similar (46 of 56 positive versus 43 of 56 positive, respectively) and comparable with results with anti-MSA in formalin-fixed tissue (43 of 55 positive). However, the proportion of cells stained by antidesmin was higher in alcohol-fixed tissue than in formalin-fixed tissue. Staining with antimyoglobin and anti-CKM was much less satisfactory, with positivity rates of 17 of 37 and 11 of 57, respectively, in formalin-fixed rhabdomyosarcomas. Immunostaining of muscle markers revealed evidence of myogenesis in six undifferentiated sarcomas and in two sarcomas with inadequate histologic study on hematoxylin-eosin-stained sections. However, positivity was also noticed in samples of fibromatosis, Wilms' tumor, ectomesenchyoma, peripheral primitive neuroectodermal tumor, renal rhabdoid tumor, myositis ossificans, malignant fibrous histiocytoma, and embryonal sarcoma of the liver. The authors conclude that combined use of antidesmin and anti-MSA enhances the diagnosis of childhood sarcomas, especially when employed with other techniques such as electron microscopic study.

Actins↗
PubMed2006

Maternal medication use and the risk of brain tumors in the offspring: the SEARCH international case-control study.

N-nitroso compounds (NOC) have been associated with carcinogenesis in a wide range of species, including humans. There is strong experimental data showing that nitrosamides (R(1)NNO.COR(2)), a type of NOC, are potent neuro-carcinogens when administered transplacentally. Some medications are a concentrated source of amides or amines, which in the presence of nitrites under normal acidic conditions of the stomach can form NOC. Therefore, these compounds, when ingested by women during pregnancy, may be important risk factors for tumors of the central nervous system in the offspring. The aim of the present study was to test the association between maternal use of medications that contain nitrosatable amines or amides and risk of primary childhood brain tumors (CBT). A case-control study was conducted, which included 1,218 cases and 2,223 population controls, recruited from 9 centers across North America, Europe and Australia. Analysis was conducted for all participants combined, by tumor type (astroglial, primitive neuroectodermal tumors and other glioma), and by age at diagnosis (< or =5 years; >5 years). There were no significant associations between maternal intake of medication containing nitrosatable amines or amides and CBT, for all participants combined and after stratification by age at diagnosis and histological subtype. This is the largest case-control study of CBT and maternal medications to date. Our data provide little support for an association between maternal use of medications that may form NOC and subsequent development of CBT in the offspring.

Adolescent↗
PubMed1992

Childhood brain tumors that occupy more than one compartment at presentation. Multiple compartment tumors.

Children whose brain tumor involves two or more compartments at presentation differ clinically and pathologically from children whose brain tumor is confined to one compartment. In this study of 3,291 children with a brain tumor, at least 10% had a tumor that occupied two or three compartments at first hospitalization. Infratentorial tumors occupying multiple compartments were 1.7 times more likely to involve the cervicomedullary junction than the mesodiencephalic junction. Younger children (1-3 years) were more likely to have had multiple compartment tumors than older children. Children whose tumor was limited to the infratentorial compartment had a longer survival than children whose tumor also occupied other compartments. Ependymoma, anaplastic ependymoma, and astrocytoma (nos) were over represented among infratentorial multiple compartment tumors. Pilocytic astrocytoma, primitive neuroectodermal tumor (medulloblastoma), and desmoplastic medulloblastoma were less likely to have occupied multiple compartments at the time of the first surgical exploration. The distributions of histologic features in tumors at the cervicomedullary junction differed from those in tumors limited to the posterior fossa or to the spinal canal. Seizures were more likely if the tumor was confined to the supratentorial compartment, whereas nausea or vomiting and headache were more likely if the tumor was confined to the infratentorial compartment. Children whose tumor was confined to the spinal canal were significantly more likely to have bladder symptoms and back and/or abdominal pain than those whose tumor also involved compartments above the foramen magnum. We conclude that brain tumors apparently confined to one compartment at presentation are biologically and structurally different from tumors evident in two or more compartments.

Adolescent↗
PubMed2003

MR imaging of glioblastoma in children: usefulness of diffusion/perfusion-weighted MRI and MR spectroscopy.

BACKGROUND: Glioblastoma is relatively uncommon in childhood and maybe difficult to differentiate from other brain tumors such as primitive neuroectodermal tumor, ependymoma, or benign astrocytoma. OBJECTIVE: To describe the characteristic MR features in children with glioblastoma and to evaluate the usefulness of diffusion and perfusion MR imaging and MR spectroscopy in pediatric glioblastoma. MATERIALS AND METHODS: MR imaging in 11 children (12 tumors) with biopsy-proven glioblastoma was reviewed retrospectively. In one patient, there was a recurrent glioblastoma. We reviewed CT and MRI imaging for tumor location, density/signal intensity, and enhancement pattern. Routine MR imaging was performed with a 1.5-T scanner. In six patients, diffusion-weighted MR images (DWIs) were obtained with a single-shot spin echo EPI technique with two gradient steps, and apparent diffusion coefficients (ADCs) were calculated. Using the gradient EPI technique, perfusion-weighted MR images (PWIs) were obtained in four patients from the data of dynamic MR images. The maximum relative cerebral blood volume (rCBV) ratio was calculated between the tumor and contralateral white matter in two cases. In three patients, proton MR spectroscopy was performed using a single voxel technique with either STEAM or PRESS sequences. The locations of the tumor were the thalamus and basal ganglia ( n=8), deep white matter ( n=3), and brain stem ( n=1). RESULTS: Intratumoral hemorrhage was seen in four tumors. The tumors showed high-signal intensity or DWIs, having a wide range of ADC values of 0.53-1.30 (mean +/-SD=1.011+/-0.29). The maximum rCBV ratios of glioblastoma were 10.2 and 8.5 in two cases. MR spectroscopy showed decreased N-acetylaspartate (NAA) and increased choline in three cases. The MR findings of glioblastoma in children were: a diffusely infiltrative mass with hemorrhage involving the deep cerebral white matter, thalami, and basal ganglia. CONCLUSION: Diffusion/perfusion MR imaging and MR spectroscopy are very helpful in diagnosing glioblastoma, determining the biopsy site, and evaluating tumor recurrence.

Adolescent↗
PubMed2002

Pediatric brain tumors: statistics of SNUH, Korea (1959-2000).

OBJECTIVE: To investigate the age, gender, location and pathologic diagnosis of brain tumors in pediatric patients (less than 16 years old), we reviewed 677 patients who were operated on at the Department of Neurosurgery, Seoul National University Hospital (SNUH) during the period from January 1959 to June 2000. PATIENTS AND METHODS: Only tumors for which pathologic specimens were available were included. Tumors of bone origin, purely extradural mass, nontumorous cystic lesions, and vascular malformations were excluded. The mean age of the 677 patients was 7.8 years and the gender ratio (male-to-female ratio), 1.4:1. Supratentorial tumors (60.0%) were more common than infratentorial tumors (39.1%). Pathological examination showed that the most common tumors were astrocytic tumors (25.7%), medulloblastomas (17.9%), craniopharyngiomas (12.0%), germ cell tumors (11.2%), supratentorial primitive neuroectodermal tumors (ST-PNETs) (5.5%), and neuronal tumors (5.2%). Choroid plexus tumors and ependymal tumors occurred more frequently in early childhood, while pituitary adenomas and non-teratomatous germ cell tumors occurred more frequently in older children. While most tumors were more predominant in males, oligodendroglial tumors and pituitary adenomas were more predominant in females. CONCLUSIONS: The relative incidences of germ cell tumors, neuronal tumors, and oligodendroglial tumors increased after the introduction of magnetic resonance imaging (MRI). In contrast, the incidence rates of medulloblastomas and ependymal tumors decreased.

Academic Medical Centers↗
PubMed2003

Absence of detectable alterations in the putative tumor suppressor gene BTRC in cerebellar medulloblastomas and cutaneous basal cell carcinomas.

The sonic hedgehog signal transduction pathway is aberrantly activated in the majority of cutaneous basal cell carcinomas and a subset of cerebellar medulloblastomas. The latter tumors may also show activation of the wingless (Wnt) signaling pathway. In Drosophila, the F-box/WD40-repeat containing protein Slimb has been shown to function as an intracellular negative regulator of both pathways. The BTRC gene (beta-transducin repeat-containing protein) is a human homolog of Slimb that is located at 10q24.3, a chromosome region frequently deleted in medulloblastomas. Here, we report on the mutational analysis of BTRC in 91 human tumors, including 66 primitive neuroectodermal tumors (PNETs) of the central nervous system (62 medulloblastomas and 4 supratentorial PNETs) and 25 cutaneous basal cell carcinomas (BCCs). These analyses revealed no tumor-associated BTRC mutations. BTRC transcripts were expressed in non-neoplastic brain tissue, normal skin, as well as in all PNETs and BCCs analyzed by real-time reverse transcription-PCR. Two novel BTRC transcript variants were expressed at higher levels in non-neoplastic brain tissue than in normal skin and the investigated tumors. Taken together, our results indicate that PNETs and BCCs neither show mutations nor loss of mRNA expression of BTRC. Therefore, BTRC alteration does not appear to be involved in the pathogenesis of these neoplasms.

Base Sequence↗
PubMed2003

Megatherapy with hematopoietic stem cell rescue as a preoperative treatment in unresectable pediatric malignancies.

BACKGROUND/PURPOSE: To improve the quality of life and prognosis of the patients with advanced pediatric malignant tumors, the authors have used megatherapy (MT) with hematopoietic stem cell transplantation (SCT) before surgery. To elucidate the impact of preoperative MT on the treatments of pediatric advanced malignancies, the authors reviewed the timing of surgery, preoperative condition, postoperative recovery, and outcome. METHODS: Between 1991 and 2001, 24 children with malignant tumors received MT with SCT before surgery, and 19 tumors were resected after SCT. These tumors included 12 neuroblastomas, 2 hepatic tumors, 2 peripheral primitive neuroectodermal tumors, one rhabdomyosarcoma, one Wilms' tumor, and one yolk sac tumor. RESULTS: The mean duration of white blood cell (WBC) recovery (>1,000/mm3) and platelet recovery (>50,000/mm3) after SCT was 17.1 and 42.5 days, respectively. Distant metastases were controlled in 9 of 15 cases. The tumors were resected completely in 14 cases (73.7%), and complete remission (CR) was achieved after surgery in 9 cases (47.4%). There was no postoperative complication or remarkable functional impairment. At 7 months to 7 years after diagnosis, 9 patients are alive without disease, one with disease, 6 have died of recurrent tumor, and 2 have died of chemotherapy-associated complications. CONCLUSIONS: The current study suggested that MT with SCT before surgical resection contributes to increase in resectability and achieving CR. In the treatment of advanced pediatric malignancies, especially in the case of unresectable tumor, preoperative MT with SCT should be considered.

Adolescent↗
PubMed2000

Clear cell sarcoma of the kidney: a review of 351 cases from the National Wilms Tumor Study Group Pathology Center.

We reviewed 351 cases of clear cell sarcoma of the kidney (CCSK), including 182 cases entered on National Wilms Tumor Study Group (NWTSG) trials 1-4 for which clinical follow-up information was available. Tumors were restaged using NWTS 5 criteria. Mean age at diagnosis in the NWTS group was 36 months with a range of 2 months to 14 years. The male to female ratio was 2:1. Typical gross features included large size (mean diameter 11.3 cm), a mucoid texture, foci of necrosis, and prominent cyst formation. Nine major histologic patterns were identified (classic, myxoid, sclerosing, cellular, epithelioid, palisading, spindle, storiform, and anaplastic); virtually all tumors contained multiple patterns that blended with one another. Immunohistochemical stains were performed on 45 cases; only vimentin was consistently immunoreactive. Consistently negative results with other antibodies helped exclude other tumors in the differential diagnosis; all CCSKs were cytokeratin-negative, including epithelioid tumors that mimicked Wilms tumor, and MIC2-negative, including cellular tumors that mimicked primitive neuroectodermal tumor. The p53 gene product was rarely overexpressed in non-anaplastic CCSKs, but strikingly overexpressed in two of three anaplastic CCSKs. Overall survival was 69%. Multivariate analysis revealed four independent prognostic factors for survival: treatment with doxorubicin, stage, age at diagnosis, and tumor necrosis. Of note, stage 1 patients had a remarkable 98% survival rate. No other histologic or clinical variable independently correlated with survival.

Adolescent↗
PubMed1997

March 1997--4 year old girl with ring chromosome 22 and brain tumor.

A four year old Caucasian girl with a constitutional ring chromosome 22 abnormality and developmental delay presented with increasing ataxia and a six week history of non-specific symptoms. Imaging studies demonstrated a large third ventricular tumor with apparent involvement of the septum. Microscopic and immunohistochemical studies demonstrated an atypical teratoid/rhabdoid tumor. This tumor is compared and contrasted to peripheral malignant rhabdoid tumors and central primitive neuroectodermal tumors. The role of a putative tumor suppressor gene on the long arm of chromosome 22 in the pathogenesis of these tumors is also discussed.

Brain Neoplasms↗
PubMed2000

Frequency of malignant solid tumors in children.

OBJECTIVE: To find out the frequency of malignant solid tumors in children (< 15 years). SETTING: All cases of pediatric malignant solid tumors which were diagnosed in the section of histopathology at the Aga Khan University Hospital, Karachi during the period of two years. METHODS: These tumors were initially evaluated on H&E stained sections and special stains were also performed whenever indicated. The undifferentiated tumors were evaluated immunohistochemically by using a panel of antibodies on sections from routinely processed, formalin fixed, paraffin embedded tissue blocks. RESULTS: Of two hundred and fifty three (253) consecutive cases of paediatric malignant solid tumors, lymphoma (26.1%) was the most common tumor followed by central nervous system tumors (16.6%), osteosarcoma (7.5%), rhabdomyosarcoma (6.7%), neuroblastoma (5.1%), Wilm's tumor (5.1%), Ewing's sarcoma (4.7%), retinoblastoma (4.7%), germ cell tumor (4.4%) and primitive neuroectodermal tumor (4%) in order of frequency. In seven cases (2.8%), the nature of lesion remained undetermined even after immunohistochemical staining. Rest of malignant tumors (12.3%) included the rare entities like synovial sarcoma, nasopharyngeal carcinoma, leiomyosarcoma, malignant schwannoma and thyroid carcinoma, etc. CONCLUSION: Lymphoma was the most frequent Paediatric tumor. The frequency of childhood central nervous system tumors was quite high as compared to the other series from different regions of Pakistan.

Adolescent↗
PubMed1992

Expression of glial fibrillary acidic protein in human medulloblastoma cells treated with recombinant glia maturation factor-beta.

Medulloblastoma, a common pediatric brain tumor, is a primitive neuroectodermal tumor which often displays neuronal and/or glial characteristics. We have investigated the consequences of treating cell lines derived from a human medulloblastoma with glia maturation factor-beta (GMF-beta), a protein found in mammalian brain. GMF-beta promotes growth arrest and morphological alteration of cultured glioma and neuroblastoma cells. The proliferation of medulloblastoma cells was arrested 24-48 hr after exposure to human recombinant GMF-beta. During the same period, treated cells acquired a morphology similar to that of mature astrocytes. By 72 hr, all treated cells bound an antibody against glial fibrillary acidic protein (GFAP), a distinguishing biochemical feature of mature astrocytes. Immunoreactivity was accompanied by de novo expression of GFAP mRNA. Our observations are the first demonstration of the induction of morphological and biochemical characteristics of mature astrocytes in cultured medulloblastoma-derived cells by an exogenous factor.

Cell Division↗
PubMed1991

Intracranial tumor in infants: characteristics, management, and outcome of a contemporary series.

Since 1980, 22 patients less than 2 years of age have been treated for intracranial tumors at our institution. The most common presentation was elevated intracranial pressure associated with ventriculomegaly (73%). The diagnosis was made by computed tomography or magnetic resonance imaging and confirmed surgically in every case. In 68% of cases, the tumor involved midline structures in the central nervous system. Tumors were infratentorial in 29% of patients less than 1 year of age and in 60% of those more than 1 year of age. Most tumors were either primitive neuroectodermal tumors (41%, 7 of 9 located in midline posterior fossa structures) or astrocytomas (27%, 5 of 6 located in the hypothalamus, chiasm, or optic nerve). Twenty patients had gross or subtotal tumor resection. Surgical mortality and neurological morbidity were 10% and 5%, respectively. Of 5 patients who underwent a second operation for tumor recurrence, 3 demonstrated a change in the pathological features of the tumor from those of the original diagnosis. Of 10 surgical survivors with malignant tumors, 8 received chemotherapy and 5 radiation therapy. Radiation was not administered before 1 year of age. The overall 1-year survival was 70%, and 2-year survival was 58%. Two-year survival for benign and malignant tumors was not significantly different. We think that the interdisciplinary efforts directed toward the treatment of these tumors has improved survival and that all children should be offered entry to a research protocol and aggressive treatment.

Brain Neoplasms↗
PubMed1985

Pathology of midline brain tumors. Immunocytochemical tumor markers and classificatory aspects.

Our understanding of the pathology of human brain tumors has considerably increased in recent years thanks to investigation of nervous tissue markers which can be demonstrated by immunocytochemical techniques in sections of neurosurgical tissue specimens. This development is presented here in a review of the most important entities among midline brain tumors. Detection of neural differentiation markers such as glial fibrillary acidic protein (GFAP), S 100 protein (S 100 p), neurofibrillary proteins and neuron-specific enolase (NSE) greatly contributed to clarifying the histogenesis and differentiation potential of undifferentiated small-cell tumors grouped as primitive neuroectodermal tumors (PNETs) which include cerebellar medulloblastomas and pinealoblastomas as well as neuroblastomas and ependymoblastomas. Among medulloblastomas, the desmoplastic variety (formerly called by some "arachnoidal sarcoma of the cerebellum") shows frequent glioneuronal differentiation. Monoclonal antibodies recognizing antigenic determinants specific for tumor types and grades of malignancy/differentiation will gain significance in brain tumor diagnosis, as demonstrated in some examples. Despite the development of more objective ("scientific") criteria for typing human brain tumors, the "art" of classical histopathologic evaluation is not replaced but supplemented by the wealth of data supplied by such modern accomplishments.

Astrocytoma↗
PubMed2006

Medulloblastoma simulating acute myeloid leukemia: case report with a review of "myeloid antigen" expression in nonhematopoietic tissues and tumors.

Medulloblastoma is a primitive neuroectodermal tumor arising in the posterior fossa usually in the first decade of life. Systemic metastases are infrequent at diagnosis and usually occur after surgical resection or shunt placement. We report a rare case of medulloblastoma in an 18-year-old woman who presented with headache, leukopenia, and anemia. Neurologic examination was normal. Bone marrow evaluation revealed primitive cells morphologically resembling blasts. By flow cytometry, these cells lacked CD45 and expressed CD13/33, CD15, CD34, HLA-DR, and strong CD56. The presence of myeloid antigens and CD34 suggested acute myeloid leukemia; however, the bone marrow core biopsy architecture and tumor cells in cerebrospinal fluid were more compatible with a nonhematopoietic tumor. Further workup revealed a cerebellar mass, and a diagnosis of desmoplastic medulloblastoma was made. To our knowledge, this is the first reported case of a nonhematopoietic small round blue-cell tumor expressing multiple myeloid antigens and CD34 by flow cytometry.

Adolescent↗
PubMed1999

Brain tumors in children under 3 years of age. Recent experience (1987-1997) in 39 patients.

Brain tumors in children under 3 years of age differ in clinical presentation and pathological behavior from those in older patients. In this study, we reviewed data from 39 children (24 males and 15 females) under 3 years of age who were treated for intracranial brain tumors since the introduction of magnetic resonance imaging. The purpose was to assess correlations between clinicoradiological and treatment-related factors, and their impact on prognosis. The following factors were analyzed: sex, age, duration of symptoms, intracranial hypertension on admission, tumor location, surgical removal and histology. Associations between these factors and correlations with prognosis were determined using bivariate analyses (chi(2) test) and Kaplan-Meier survival curves. Collins' concept of a period of risk recurrence was tested. Mean follow-up was 41 months (range 0-136). In March 1998, 20 children were still alive (51.2%) with a mean survival time of 65 months (range 2-136). The incidence of supratentorial tumors was significantly higher in children less than 1 year old (p = 0.027). Lateral tumors were 9/10 (90%) supratentorial versus only 7/26 (27%) midline tumors (p = 0.001). Outcome (dead or alive) was significantly better (p = 0.037) for low-grade astrocytomas (9/12 = 75% survival) when compared to ependymomas (2/6 = 33%) and primitive neuroectodermal tumors (3/12 = 25%). Total tumor removal was achieved in 20 cases and was associated with a better outcome (65 vs. 33% survival; p = 0.049). Survival analysis confirmed a worse prognosis for children with ependymomas and primitive neuroectodermal tumors (p = 0.011) and revealed a worse survival for children with intracranial hypertension on admission (p = 0.047). Total tumor removal was associated with a longer survival, although not significantly (p = 0. 077). Finally, we found no exceptions to Collins' law.

Brain Neoplasms↗
PubMed1997

Expression of c-met proto-oncogene product (c-MET) in benign and malignant bone tumors.

The expression of c-met proto-oncogene product (c-MET) has been reported to be related to invasive growth or tumor stage in some tumors, but little is known concerning the significance of c-MET expression in bone tumors. With use of formalin-fixed, paraffin-embedded tissue specimens and polyclonal antibody for c-MET, we studied the expression of c-MET in 122 cases of malignant bone tumors (43 osteosarcomas, 24 chondrosarcomas, 21 malignant fibrous histiocytomas of bone, 16 Ewing's sarcoma versus primitive neuroectodermal tumors, 18 chordomas), 65 cases of benign tumors and tumor-like lesions (including 8 giant cell tumors of bone, 8 chondroblastomas, 12 enchondromas, 7 osteochondromas, 10 fibrous dysplasias), 7 cases of articular cartilaginous tissue, and 10 cases of fetal vertebral tissue consisting of foci of enchondral ossification and notochordal tissue. In malignant tumors, c-MET expression was most frequently detected in chordoma (94.4%), followed by chondrosarcoma (54.2%) and osteosarcoma (23.3%). Among the osteosarcoma specimens, c-MET expression was frequently detected in the chondroblastic subtype (66.7%), but the incidence was low in the cases with other subtypes of osteosarcoma. We found no significant correlation between the c-MET expression and the histologic grade of malignancy in either osteosarcoma or chondrosarcoma. c-MET expression was either rarely observed or completely negative in malignant fibrous histiocytomas of bone (4.8%) and primitive neuroectodermal tumors (0%). In benign tumors and tumor-like lesions, c-MET expression was frequently detected in cartilaginous tumors, such as chondroblastoma (62.5%), enchondroma (66.7%), and osteochondroma (71.4%), but no expression was observed in giant cell tumors of bone or any other benign tumors or tumor-like lesions. In normal tissue, c-MET expression was frequently detected in the articular cartilage (100%) and notochord (70.0%) specimens examined. We conclude that c-MET expression as frequent as that observed in the notochordal tissue, chordomas, articular cartilage, and cartilaginous tumors is related to the development of both normal tissue and chondroid tumors.

Adolescent↗
PubMed1992

Midline brain tumors in MSV-SV 40-transgenic mice originate from the pineal organ.

Adult transgenic mice expressing the large T-antigen of the Simian virus 40 (SV 40) under the control of the Moloney murine sarcoma virus (MSV) enhancer and the SV 40 promoter develop inheritable uniform midline brain neoplasms showing features of primitive neuroectodermal tumors. The origin and histogenesis of these tumors were investigated in the present study. The brain and pineal organ of fetal and young transgenic mice less than 3 months old displayed normal macroscopic and microscopic features. In 3.5-month-old animals, the pineal organ was considerably enlarged due to hyperplasia, finally leading to tumor formation. Immunocytochemical demonstration of large T-antigen showed that this oncoprotein was already expressed in the nuclei of certain cells in the pineal organ of fetuses (16 and 18 days old) and newborn animals, but was absent from all other parts of the brain. The immunocytochemical demonstration of S-antigen (arrestin), a highly characteristic marker for pinealocytes, was used for further characterization of the large T-antigen-immunoreactive cells. The fetal pineal organ did not contain immunoreactive S-antigen. This first occurred in certain pinealocytes of newborn mice. Double immunostaining revealed that in newborn and older transgenic mice the immunoreactive large T-antigen was exclusively found in nuclei of cells containing S-antigen immunoreaction in their cytoplasm. Thus, transformed pinealocytes appear as stem cells of the experimental tumors. The results of this study suggest that primitive neuroectodermal tumors and the normal tissue from which they originate share certain molecular and immunocytochemical features.

Animals↗
PubMedDate not supplied

Chemotherapy with the "8 in 1" protocol for malignant brain tumors in children: a population-based study in Finland.

We evaluated the outcome of 68 children with malignant brain tumors treated with the "8 in 1" chemotherapy protocol in Finland from 1986 to 1993, comparing 5-year survival rates with those for a historical control group (from 1975 to 1985). For all malignant brain tumors, overall survival was 43% (vs 28% in the control group; P <0.05), and progression-free survival (PFS) was 43% (vs 23%; P <0.05). For medulloblastoma and primitive neuroectodermal tumor, survival was 63% (vs 35%; P <0.05), and the corresponding PFS was 59% (vs 35%; P = 0.15). For high-grade glioma, both the survival rate and the PFS were 27% (vs 17%; P = NS). Thus the outcome was significantly better for our "8 in 1" -treated patients than for the historical controls, especially among the children with primitive neuroectodermal tumor and medulloblastoma. In contrast, those with high-grade gliomas and brain stem tumors seem to have received little benefit; different, more effective treatments are needed for these patients.

Adolescent↗