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PubMed2005

Promoter hypermethylation profile of RASSF1A, FHIT, and sFRP1 in intracranial primitive neuroectodermal tumors.

Medulloblastomas (MBs) and supratentorial primitive neuroectodermal tumors (SPNETs) are histologically alike intracranial PNETs found in different anatomical locations of the brain. Current evidence suggests that hypermethylation of promoter CpG islands is a common epigenetic event in a variety of human cancers. The aim of this study was to investigate whether promoter hypermethylation of putative tumor suppressor genes was involved in both types of intracranial PNETs. We examined the methylation status at promoter regions of RASSF1A, FHIT, and sFRP1 by methylation-specific polymerase chain reaction in a cohort of 25 primary MBs, 9 primary SPNETs, and 3 MB and 2 SPNET cell lines. Our results revealed no promoter hypermethylation of RASSF1A, FHIT, and sFRP1 in 2 normal cerebellar and 5 normal cerebral tissue specimens examined. In contrast, promoter hypermethylation of RASSF1A was detected in 100% of primary MBs, 67% (6/9) of primary SPNETs, and all PNET cell lines. The frequency of promoter hypermethylation of RASSF1A was significantly lower in SPNETs than in MBs (Fisher exact test, P = .014). Treatment of RASSF1A-deficient PNET cell lines with 5-aza-2'deoxycytidine, a demethylating agent, restored RASSF1A expression, providing evidence that promoter hypermethylation contributes to transcriptional silencing. In addition, promoter hypermethylation of FHIT and sFRP1 was detected in 22% (2/9) and 11% (1/9) of SPNETs, respectively, but not in any MBs studied. In conclusion, our study demonstrates that promoter hypermethylation of RASSF1A is a common event in intracranial PNETs, whereas FHIT and sFRP1 are epigenetically affected in a fraction of SPNETs.

Acid Anhydride Hydrolases↗
PubMed2006

Transverse myelitis after therapy for primitive neuroectodermal tumors.

Traditional therapy for malignant primitive neuroectodermal tumors in children includes surgery, multi-agent chemotherapy, and radiation. Given the poor prognosis with conventional therapy alone, newer treatment approaches have incorporated high-dose chemotherapy followed by autologous stem cell rescue. Treatment with chemotherapy and radiation is not without unanticipated and unwanted side effects. Specifically, radiation-induced damage to the central nervous system can occur, though the frequency is thought to be acceptably low. This report describes two cases of treatment-related transverse myelitis in patients who received induction chemotherapy and craniospinal irradiation followed by high-dose chemotherapy with autologous stem cell rescue. Other patients treated with a similar strategy but different sequence and timing of treatment did not experience symptoms of myelitis, suggesting that the specific timing of radiation in relationship to the chemotherapy may be of critical importance.

Adolescent↗
PubMed2003

Organ-confined primitive neuroectodermal tumor arising from the kidney.

Primitive neuroectodermal tumor (PNET) of the kidney is a rare entity with high malignant potential. Of the reported cases of renal PNET, patients presented with metastatic disease and had a poor response to therapy. The authors describe a rare case of an organ-confined primary PNET arising from the kidney in a 16-year-old girl who presented with vague abdominal pain. Tumor behavior and treatment modalities are discussed.

Abdominal Pain↗
PubMed2005

Treatment strategies for high-risk medulloblastoma and supratentorial primitive neuroectodermal tumors. Review of the literature.

Primitive neuroectodermal tumors (PNETs) are malignant tumors with a high propensity to disseminate throughout the cerebrospinal fluid. Current treatment guidelines are largely determined by clinically based prognostic factors, the most important of which are tumor location and the extent of tumor spread. Although the cure rate for high-risk PNETs has improved, the irreversible sequelae of craniospinal axis radiation treatment in patients who survive have motivated researchers to investigate more fully which patients can safely receive less treatment. The author reviews the literature, describes currently available treatment options for patients with high-risk PNETs, and discusses strategies aimed at improving outcome and refining prognosis that are currently being explored.

Age Factors↗
PubMed1999

[A case of primitive neuroectodermal tumor of the kidney].

A primitive neuroectodermal tumor (PNET) is a solid tumor originating from the neural crest. This tumor is known to occur in the central nervous system and soft tissue, but recently determined to also invade the kidney. Although primary renal PNET is very rare, we encountered a case of primary renal PNET with multiple lung metastasis. This case was a 35-year-old man with a chief complaint of macroscopic hematuria, which he noticed in January 1996. He was hospitalized because of right renal tumor detected with ultrasonography. On CT scan, a low-density solid tumor with a maximum diameter of 8 cm was visualized in the right kidney. Low-signal and high-signal tumorous lesions were demonstrated in the same region on T 1-weighted and T 2-weighted MR images, respectively. Then right radical nephrectomy was performed on Feb. 5, 1996. On histopathological observation, the tumor was composed of small tumor cells with solid growth. Immunohistochemical staining revealed that the tumor was positive for CD 99. Thus our final diagnosis was primary right renal PNET. Although 2 metastatic lesions with a diameter of about 1 cm were observed in the right lower lung before the time of surgery, pulmonary metastatic lesions markedly increased in number 3 months after surgery. Thus we initiated CAP chemotherapy with cyclophosphamide, doxorubicin, and CDDP. After 3 cycles, pulmonary metastatic lesions disappeared at CT scan, indicating complete remission. However, a tumor with a maximum diameter of about 10 cm recurred in the retroperitoneum 7 months after complete remission. Although 2 cycles of CAV/PE therapy with cyclophosphamide, doxorubicin, vincristine, CDDP, and VP-16 were performed following resection of the retroperitoneal tumor, he showed no response and decreased 24 months after surgery.

Adult↗
PubMed2005

Molecular detection of EWS-Ets fusion transcripts and their clinicopathologic significance in Ewing's sarcoma/peripheral primitive neuroectodermal tumor.

BACKGROUND: Ewing's sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) is often difficult to distinguish from other small round cell tumors. The EWS-Ets gene fusions that result from chromosomal translocations in this tumor provide potential molecular diagnostic markers. To apply these molecular markers to commonly available archival materials, we evaluated the feasibility of detecting EWS-Ets including EWS-Fli1 and EWS-ERG fusion transcripts in paraffin-embedded tissues and its diagnostic value for detecting ES/pPNET. METHODS: Thirteen paraffin-embedded samples of ES/pPNETs were retrieved from archives. Thirteen cases of other tumors with small round cell features (including rhabdomyosarcoma, neuroblastoma, lymphoma, small cell carcinoma, and desmoplastic small round cell tumor) were used as negative controls. Beta-actin and beta2-microglobulin were used as internal controls. A nested reverse transcriptase-polymerase chain reaction (RT-PCR)-based assay was performed to detect the EWS-Fli1 and EWS-ERG fusion transcripts. RESULTS: Beta-actin and beta2-microglobulin were detected in 10/13 and 13/13 ES/pPNETs, respectively. EWS-Fli1 fusion transcripts were detected in 11 of 13 (85%) ES/pPNETs. Three chimeric transcripts, all EWS-Fli1, were detected in ES/pPNET samples. Among 11 EWS-Fli1-positive cases, 7 cases had a type I fusion transcript involving fusion of EWS exon 7 with Fli1 exon 6, 2 cases had a type II fusion transcript involving EWS exon 7 with Fli1 exon 5, and 2 cases expressed fusion transcripts involving EWS exon 7 and Fli1 exon 8. Type I EWS-Fli1 fusion predominated over other types. Fusion types could not be distinguished in the remaining 2 cases. Thirteen negative controls did not show detectable chimeric messages. There was a significant relationship between EWS-Fli1 fusion transcripts and CD99 expression. CONCLUSIONS: Molecular detection of EWS-Fli1 fusion transcripts in formalin-fixed paraffin-embedded material by nested RT-PCR is feasible and is useful for the diagnosis and differential diagnosis of ES/pPNETs.

Adolescent↗
PubMed1993

Reverse transcriptase PCR amplification of EWS/FLI-1 fusion transcripts as a diagnostic test for peripheral primitive neuroectodermal tumors of childhood.

The peripheral primitive neuroectodermal tumors (pPNETs) of childhood, including Ewing's sarcoma, peripheral neuroepithelioma, and Askin's tumor, often present significant diagnostic challenges for the anatomic pathologist. One consistent feature of these tumors is the presence of the t(11;22)(q24;q12) in tumor cells, and this translocation has been useful as a marker for this group of tumors. The recent cloning of the t(11;22) breakpoint has revealed the fusion of the human FLI-1 gene on chromosome 11q24 with a gene of unknown function called EWS on 22q12, and fusion transcripts have been detected. These findings have raised the possibility of using molecular genetic analysis as a tool to diagnose pPNETs. To this end, we have tested pPNETs for the presence of EWS/FLI-1 fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) using EWS and FLI-1 specific primers. Eight (80%) of 10 pPNET cell lines were positive for amplified products using this technique. These results were confirmed by Southern analysis, which revealed rearrangements of EWS using genomic EWS probes in all eight positive cell lines. We then tested 20 primary pPNET tumors, and identified fusion transcripts by RT-PCR in 18 (90%) of these cases. Cloning and sequencing of PCR products confirmed the presence of EWS and FLI-1 sequences in these products. Furthermore, fusion transcripts were not detected by this technique in a series of non-pPNET pediatric solid tumors. Detection of EWS/FLI-1 fusion transcripts by RT-PCR therefore provides a novel adjunctive tool in the diagnosis of pPNETs.

Adolescent↗
PubMedDate not supplied

Risk factors for astrocytic glioma and primitive neuroectodermal tumor of the brain in young children: a report from the Children's Cancer Group.

We conducted a matched case-control study to investigate risk factors for the two most common types of brain tumors in children, astrocytic glioma and primitive neuroectodermal tumor (PNET). Since the study focused on gestational exposures, we restricted it to young children because these exposures would be expected to act early in life. Parents of 155 astrocytic glioma cases, 166 PNET cases, and controls identified by random digit dialing completed telephone interviews. Few associations occurred with the hypothesized risk factors, which were gestational exposure to alcohol, hair coloring products, farms, and substances containing N-nitroso compounds (passive smoking, makeup, incense, new cars, pacifiers, baby bottles, beer). Of the products studied that contain N-nitroso compounds, only beer was associated with a significantly increased risk of either tumor type [odds ratio (OR) for PNET = 4.0; 95% confidence interval (CI), 1.1-22.1; P = 0.04]. Elevated ORs for PNET were observed for farm residence of the mother during the pregnancy (OR = 3.7; 95% CI, 0.8-23.9; P = 0.06) and of the child for at least a year (OR = 5.0; 95% CI, 1.1-46.8; P = 0.04). Significant associations with astrocytoma were observed for mother's use of kerosene (OR = 8.9; 95% CI, 1.1-71.1; P = 0.04) and birth by Caesarean section (OR = 1.8; 95% CI, 1.1-3.2; P = 0.03). History of miscarriage was associated with a lower risk of PNET (OR = 0.5; 95% CI, 0.3-0.9; P = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Spontaneous↗
PubMed2003

Addition of ifosfamide and etoposide to standard chemotherapy for Ewing's sarcoma and primitive neuroectodermal tumor of bone.

BACKGROUND: Ewing's sarcoma and primitive neuroectodermal tumor of bone are closely related, highly malignant tumors of children, adolescents, and young adults. A new drug combination, ifosfamide and etoposide, was highly effective in patients with Ewing's sarcoma or primitive neuroectodermal tumor of bone who had a relapse after standard therapy. We designed a study to test whether the addition of these drugs to a standard regimen would improve the survival of patients with newly diagnosed disease. METHODS: Patients 30 years old or younger with Ewing's sarcoma, primitive neuroectodermal tumor of bone, or primitive sarcoma of bone were eligible. The patients were randomly assigned to receive 49 weeks of standard chemotherapy with doxorubicin, vincristine, cyclophosphamide, and dactinomycin or experimental therapy with these four drugs alternating with courses of ifosfamide and etoposide. RESULTS: A total of 518 patients met the eligibility requirements. Of 120 patients with metastatic disease, 62 were randomly assigned to the standard-therapy group and 58 to the experimental-therapy group. There was no significant difference in five-year event-free survival between the treatment groups (P=0.81). Among the 398 patients with nonmetastatic disease, the mean (+/-SE) five-year event-free survival among the 198 patients in the experimental-therapy group was 69+/-3 percent, as compared with 54+/-4 percent among the 200 patients in the standard-therapy group (P=0.005). Overall survival was also significantly better among patients in the experimental-therapy group (72+/-3.4 percent vs. 61+/-3.6 percent in the standard-therapy group, P=0.01). CONCLUSIONS: The addition of ifosfamide and etoposide to a standard regimen does not affect the outcome for patients with metastatic disease, but it significantly improves the outcome for patients with nonmetastatic Ewing's sarcoma, primitive neuroectodermal tumor of bone, or primitive sarcoma of bone.

Adolescent↗
PubMed2001

Abundance of apoptotic neoplastic cells in diagnostic biopsy samples is not a prognostic factor in childhood primitive neuroectodermal tumors of the central nervous system.

PURPOSE: To assess if the abundance of apoptotic tumor cells is an independent prognostic factor in primitive neuroectodermal tumors (PNET) of the central nervous system. PATIENTS AND METHODS: Formalin-fixed paraffin-embedded tumor tissue sections from 78 clinically well-characterized children with PNET were evaluated by terminal deoxytransferase-mediated deoxyuridinie-5'-triphosphate (dUTP) nick-end labeling (TUNEL). Apoptotic indices (AI) were determined by counting TUNEL-positive tumor cells either in the highest staining region (AI hot spot) or in at least 15 randomly chosen fields (AI random). The AI hot spot and AI random were then correlated with clinical variables and survival outcome. RESULTS: AI hot spot (median 0.56%; range 0%-6.54%) and AI random (median 0.30%; range 0%-3.21%) showed considerable intertumor variability. Moreover, 53% of the evaluated PNET showed a more than two-fold difference between AI hot spot and AI random, showing important intratumoral variability of the abundance of apoptotic cells in a subset of the evaluated PNET. No significant associations were found between AI hot spot and AI random with clinical variables or survival outcome. CONCLUSION: The apoptotic index does not predict survival outcome and is not specifically associated with clinical variables of prognostic significance in childhood PNET.

Apoptosis↗
PubMed2006

[Peripheral primitive neuroectodermal tumor -- PNET].

The authors describe three cases of peripheral primitive neuroectodermal tumor. The tumor was found in soft tissues of the crus, shoulder girdle and perineum, and was also located paravertebrally and epidurally at the level of L1-L2 vertebrae. Radiological findings were not specific for this disease. The results of imaging methods (sonography, CT, MRI, DSA) were important for the assessment of tumor size, its boundary and invasion of the surrounding tissues, and for the evaluation of tumor response to therapy and detection of recurrent disease. The PNET diagnosis was based on immunohistochemical, biochemical and cytogenetic examinations. One patient died 5 months after the first clinical signs were manifested; the two patients surviving for 2 and 1 3/4 years after first sign manifestation, respectively, remained in the care of cancer specialists. Key words: skeletal Ewing's sarcoma, extra-skeletal Ewing's sarcoma, Ewing's sarcoma family of tumors, peripheral primitive neuroectodermal tumor.

Adolescent↗
PubMed2004

Primary intraspinal primitive neuroectodermal tumor at conus medullaris.

A primary intraspinal primitive neuroectodermal tumor is very rare, with only 24 cases having been reported in the literature. In general this type of tumor is treated with surgery followed by radiotherapy and chemotherapy; however, the prognosis still remains poor. The case of a primary intraspinal primitive neuroectodermal tumor, at the conus medullaris in a 17 year old male patient is presented. He had suffered from paraparesis, urinary difficulty and lower back pain of 1 month duration. A thoracolumbar MRI demonstrated a 2 x 2 x 8 cm isointense intraspinal mass, on T1-weighted images, with strong contrast enhancement from the T11 to L2 level. There was no clinical or radiological evidence for the existence of an intracranial tumor. A histological examination revealed a small round cell tumor and immunohistochemical characteristics of PNET. The clinical, radiological and pathological features are discussed with a review of the literatures.

Adolescent↗
PubMed2002

Primary intraspinal primitive neuroectodermal tumor: case report of a tumor arising from the sacral spinal nerve root and review of the literature.

Primary spinal primitive neuroectodermal tumor (PNET) is a rare condition, 18 cases of which have been reported in the literature. In general, this tumor is treated with surgery followed by radiotherapy and chemotherapy, but prognosis is still poor. An 18-year-old female patient with an intradural, extramedullary mass at L3-L5 levels is presented in this report. This is the first female patient with primary spinal PNET at lumbar region, second patient with spinal nerve root origin, and third one with intradural, extramedullary localization ever reported in the literature. After surgery, she was treated with craniospinal radiotherapy and four cycles of combination chemotherapy regimen consisting of vincristine, cyclophosphamide, doxorubicin alternated with ifosfamide, and VP-16. Currently, she is asymptomatic and alive at 25 months. The histopathologic, radiologic, and clinical findings of the patient are presented and relevant literature is reviewed.

Adolescent↗
PubMed2006

Primitive neuroectodermal tumor (PNET) as second malignancy after treatment of Hodgkin's disease.

Hodgkin's disease survivors are at an increased risk of developing second malignant neoplasms including secondary bone tumors. Common secondary bone tumors are osteogenic sarcoma and fibrosarcoma. Secondary primitive neuroectodermal tumor is extremely rare in this group. We present below, a rare case of secondary PNET in an 8-year-old child with Hodgkin's disease which developed unusually early outside the radiation portal and discuss potential factors responsible for its causation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Loss of heterozygosity on 6q, 16q, and 17p in human central nervous system primitive neuroectodermal tumors.

The loss of genetic material from specific chromosomal locations in a given tumor type has been taken for evidence of the importance of tumor suppressor genes at these loci in the genesis of the tumor. The primitive neuroectodermal tumor of the central nervous system has such a loss on 17p in one-third of tumors. In this report, a detailed analysis of 17p loss in 23 tumors has been performed using 10 probes mapping to this region. In addition, an analysis for allelic deletion on chromosomes 6q, 16q, and 22q has been performed. Six of the 23 tumors showed loss of markers on 17p, and the area of common loss spanned 17p11.2 to 17pter. Five of 23 tumors showed loss of markers on 6q, and 3 showed loss on 16q. No tumor lost markers on 22q. Only one tumor showed loss at more than one location. These data suggest that primitive neuroectodermal tumors either are a heterogeneous group of tumors with more than one mechanism leading to a tumor or that more than one recessive oncogene may play a role in the genesis of these tumors.

Adult↗
PubMed1999

A cerebral primitive neuroectodermal tumor in a squirrel monkey (Saimiri sciureus).

An adult squirrel monkey with a history of long-term exposure to microwave radiation was found at necropsy to have a malignant tumor of the right cerebral cortex. Gross examination revealed a mass with expanding borders in the right frontoparietal cortex with compression of the adjacent lateral ventricle. Microscopy revealed a tumor composed of sheets of moderate-sized cells, resembling an oligodendroglioma, with clear cytoplasm and central nuclei interrupted by delicate vasculature. Malignant features were present in the form of marked nuclear pleomorphism, frequent mitotic figures, and focal necrosis. A neuronal cell origin for this tumor was supported by immunohistochemical analysis, which revealed immunopositivity for neurofilament proteins and neuron-specific enolase. Staining for vimentin and glial fibrillary acid protein was negative, except in reactive astrocytes at the tumor margins and adjacent to intra-tumoral blood vessels. Antibody activity against Ki-67 antigen, a marker of rapidly proliferating tumor cells, and p53 oncoprotein was strongly positive, indicative of the aggressive and malignant nature of this tumor. The tumor was diagnosed as a cerebral primitive neuroectodermal tumor.

Animals↗
PubMed2002

Malignant peripheral primitive neuroectodermal tumor of the kidney.

Ewing family of tumors is a group of highly aggressive neoplasias that occur most commonly in the first two decades of life. These tumors are most frequently localized in bones, less frequently in soft tissues. They usually appear as undifferentiated small round-cell tumors. With current treatment regiments, 5-year disease-free survival rates exceed 60% in patients with a localized disease. Patients with metastatic disease at the time of their first presentation have a poor prognosis. We describe a rare case of visceral primitive neuroectodermal tumor with the involvement of the kidney in a 9-year-old girl. The tumor was studied with immunohistochemistry, cytogenetics, and molecular biology methods. Strong expression of protein MIC(2) by immunochemistry (antibody HBA 71) with subsequent demonstration of a translocation consistent with t(11;22)(q24;q12) using cytogenetic and reverse transcriptase polymerase chain reaction (RT-PCR) confirmed the histopathological diagnosis of peripheral primitive neuroectodermal tumor. We detected minimal residual disease in bone marrow using RT-PCR.

Bone Marrow Cells↗
PubMed1994

Primitive neuroectodermal tumor arising in the pancreas.

Peripheral primitive neuroectodermal tumors (PNETs) are extra cranial primitive small round blue cell tumors showing histologic, immunohistochemical or electron microscopic evidence of neuroectodermal differentiation. They are most commonly encountered in the soft tissue or bone in children and young adults. We report an unusual case of a PNET arising in the pancreas. A 17-yr-old male presented with a pancreatic mass and underwent a pancreatoduodenectomy. Histologically, the neoplasm was composed of sheets of small round cells that stained for cytokeratin, neuron specific enolase, and 12E7 but not muscle specific action, desmin, common leukocyte antigen, chromogranin, synaptophysin, or other islet cell markers. The diagnosis of PNET in this unusual location was confirmed by cytogenetic analysis which showed the chromosomal translocation characteristics of PNETs, t(11;12)(q24;q12). This case highlights the difficulty in the diagnosis of PNET when it is present in visceral organs where other neuroendocrine neoplasms and adenocarcinomas are more common.

Adolescent↗