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Ewing's sarcoma and extracranial primitive neuroectodermal tumors.

The Ewing's family of tumors is comprised of bone and soft tissue, small round blue cell neoplasms of neuroectodermal origin defined by the chromosomal aberration t(11;22)(q24;q12), and closely related variants. Molecular methods now exist to facilitate diagnosis and to defect minimal residual disease. Multiagent chemotherapeutic regimens in concert with adequate local control yield improved survival rates in patients with localized disease at diagnosis. Patients with metastatic disease still suffer poor survival rates; programs attempting to cure metastatic patients with intensive therapy as facilitated by peripheral stem cell and autologous marrow rescue have shown some promise. Intensive regimens with and without rescue are being explored for high-risk patients.

Antineoplastic Agents↗

Ewing's sarcoma and peripheral primitive neuroectodermal tumors after their genetic union.

The Ewing family of tumors has been defined by the presence of an EWS-ets gene rearrangement. Using molecular techniques for the visualization of this aberration, several tumors of unusual location and histology were recently identified and added to this group. Increasing experimental data suggest that EWS-ets fusions act as transforming transcription factors. Subtractive screening of transgenic fibroblasts has led to the identification of potential targets. The authentic cellular context for these aberrant gene products is still unknown and may be diverse, however. Clinical heterogeneity has stimulated a search for genetic factors that may relate to treatment response. The effect of the EWS-ets fusion transcript structure on localized disease has been recently confirmed and frequent p16 tumor suppressor alterations have been described. The presence of metastases at diagnosis as the major predictor of outcome has been assessed on a submicroscopic level by reverse transcriptase-polymerase chain reaction. Problems arising from these studies are discussed, although the biological basis for variable disease extension remains obscure.

Heterogeneous-Nuclear Ribonucleoproteins↗

Primitive neuroectodermal tumors of the cerebral hemispheres in two siblings with TP53 germline mutation.

AWe report on two siblings (brother and sister) who developed cerebral PNETs at the age of 5 years and 6 months, respectively. Both children were treated by operation followed by polychemotherapy. The brother also received cranio-spinal irradiation. Nevertheless, the children died about 12 months and 24 months post-operatively due to extensive cerebral tumor recurrences. Shortly after having lost both of her children, the mother developed an intra-abdominal tumor, which was resected and histologically diagnosed as ovarian carcinoma. Because of this unusual familial clustering of tumors and a positive history of brain tumors and other cancers in several maternal relatives, we analyzed DNA isolated from both PNETs and the ovarian carcinoma as well as constitutional (leukocyte) DNA from the whole family for mutation of the TP53 tumor suppressor gene. This analysis revealed that all tumors were homozygous for a missense mutation at codon 213 (CGA => TGG) resulting in an amino acid exchange from arginine to tryptophane. The same mutation was present in one TP53 allele in the constitutional DNA of the mother and the children, indicating that the mother had transmitted a TP53 germline mutation to both of her children. Analysis of loss of heterozygosity at microsatellite markers from 17p confirmed deletion of the paternal (wild-type) allele in both PNETs. Further investigation of the PNETs by comparative genomic hybridization revealed multiple chromosomal abnormalities. Interestingly, some genomic changes were common to both PNETs, while many others were not, a finding suggesting substantial genomic instability, probably as a consequence of p53 inactivation.

Adult↗

Peripheral primitive neuroectodermal tumor of the stomach in a 14-year-old boy: a case report.

CONCLUSION: Although PNETs are rare malignancies, they should be considered in the differential diagnosis of submucosal gastric tumours in adolescents with clinical alarm symptoms.NET was confirmed by detection of the characteristic EWS/FLI-1 fusion gene, resulting in a reciprocal translocation t(11;22)(q24;q12). Three distinct liver metastases were detected by CT, MRI, and PET. The tumour failed to respond to neoadjuvant polychemotherapy with vincristine, etoposide, doxorubicin, and ifosfamide. Subtotal gastrectomy was performed and, surprisingly, we found diffuse metastatic infiltration of the liver that had not been detected by preoperative staging. Due to the diffuse metastatic disease the young patient's prognosis has to be considered very poor. Because of the tumour's intense expression of CD117 (c-kit), the patient is now treated with the tyrosine kinase inhibitor imatinib (STI571).

Adolescent↗

Mediastinal T-cell lymphoma in a boy 7 years after treatment of supratentorial primitive neuroectodermal tumor.

Medulloblastoma/primitive neuroectodermal tumor (PNET) is one of the most common central nervous system tumors in children and requires aggressive multimodality therapy. The authors describe a patient who developed mediastinal T-cell lymphoma 7 years after treatment of supratentorial PNET. Despite a good tumor response, the patient died during induction therapy because of invasive pulmonary aspergillosis. The authors conclude from this case that patients treated for medulloblastoma/PNET should be followed carefully for years. In addition, patients with second malignancies should be considered as a high-risk population for opportunistic infections.

Aspergillosis, Allergic Bronchopulmonary↗

Ewing sarcoma/peripheral primitive neuroectodermal tumor: adult abdominal tumors with an Ewing sarcoma gene rearrangement demonstrated by fluorescence in situ hybridization in paraffin sections.

The differential diagnosis of small round cell tumors is exhaustive and requires ancillary studies. Relatively recently, fluorescence in situ hybridization (FISH) using probes for specific gene rearrangements has gained wide acceptance. This technique is particularly useful in the differential diagnosis of Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) and desmoplastic small round-cell tumor (DSRCT). In ES/PNET, the EWS gene is juxtaposed to the FLI-1 gene in 85% of cases and to the ERG gene in another 7% of cases; the EWS gene is juxtaposed to the WTI gene in DSRCT. Documentation of the EWS gene rearrangements in EWS/PNET has previously been demonstrated in frozen tissue. We report 2 unusual cases of EWS/PNET diagnosed in abdominal tumors in adults. Although the immunohistochemical results supported a diagnosis of ES/PNET, 1 case morphologically resembled DSRCT. The diagnosis in these 2 cases was confirmed by the FISH demonstration of EWS/FLI-1 gene fusion in paraffin-embedded tissue. Thus, the usefulness of FISH demonstration of an EWS gene rearrangement with these specific probes in such unusual cases is supported and is demonstrated in paraffin-embedded tissue.

Abdominal Neoplasms↗

Peripheral primitive neuroectodermal tumor after radiotherapy.

A 41-year-old man had a peripheral neuroectodermal tumor develop at the distal third of the fibula 4 years after radiotherapy for relapsed villonodular synovitis. This type of sarcoma usually is classified into the heterogeneic group of small round-cell bone tumors as a subdivision of Ewing's sarcomas. The immuno-staining positivity of the neoplastic cells for the neuron-specific enolase allowed the authors to make the diagnosis of a tumor with neuroectodermal origin. When the histologic study confirmed the diagnosis, the patient was treated with chemotherapy, surgical excision of the tumor, and adjuvant radiotherapy. Radiotherapy is thought to be involved in the genesis of osteogenic sarcomas as it has been shown in several reports, but there is no evidence in the literature of a peripheral neuroectodermal tumor developing after radiotherapy.

Adult↗

Primitive neuroectodermal tumors of bone and soft tissue: histological subclassification and clinicopathologic correlations.

Recent reports of Ewing's sarcoma (EW) and extraskeletal Ewing's sarcoma (EEW) support the hypothesis that these tumors are neuroectodermal in origin. Primitive neuroectodermal tumors (PNET) of bone (32 cases) and soft tissue (25 cases) including those previously categorized as EW in 27 cases and EEW in 15 cases were carefully studied histologically, immunocytochemically and morphometrically, focusing on tumor cell differentiation. This study attempts to subclassify these tumors on the basis of the size of tumor cells and nuclei, their variations (uniformity or diversity), arrangement of tumor cells (rosette or non-rosette), focal differentiation to larger ganglion-like cells, and staining intensity for neural markers. All tumors were histologically subclassified as small, medium or large cell types, three basic subtypes (rosette type, abortive rosette type, non-rosette type) and four complementary subtypes (fibrillary type, non-fibrillary type, angiomatoid type, ganglion cell type). Classic EW or EEW is consistent with small or medium, non-rosette, non-fibrillary type tumors, previously described large cell EW with large, non-rosette, fibrillary or non-fibrillary type tumors, and classic neuroectodermal tumor with small or medium, rosette, fibrillary type tumors, according to the present subclassification. Clinicopathologic correlations with the different subtypes are discussed. Long-term survival, more than 5 years, was seen in patients with small cell type, and those younger than 14 years of age.

Adolescent↗

Fenretinide cytotoxicity for Ewing's sarcoma and primitive neuroectodermal tumor cell lines is decreased by hypoxia and synergistically enhanced by ceramide modulators.

Patients with disseminated Ewing's family of tumors (ESFT) often experience drug-resistant relapse. We hypothesize that targeting minimal residual disease with the cytotoxic retinoid N-(4-hydroxyphenyl) retinamide (4-HPR; fenretinide) may decrease relapse. We determined the following: (a) 4-HPR cytotoxicity against 12 ESFT cell lines in vitro; (b) whether 4-HPR increased ceramide species (saturated and desaturated ceramides); (c) whether physiological hypoxia (2% O(2)) affected cytotoxicity, mitochondrial membrane potential (DeltaPsi(m)) change, or ceramide species or reactive oxygen species levels; (d) whether cytotoxicity was enhanced by l-threo-dihydrosphingosine (safingol); (e) whether physiological hypoxia increased acid ceramidase (AC) expression; and (f) the effect of the AC inhibitor N-oleoyl-ethanolamine (NOE) on cytotoxicity and ceramide species. Ceramide species were quantified by thin-layer chromatography and scintillography. Cytotoxicity was measured by a fluorescence-based assay using digital imaging microscopy (DIMSCAN). Gene expression profiling was performed by oligonucleotide array analysis. We observed, in 12 cell lines tested in normoxia (20% O(2)), that the mean 4-HPR LC(99) (the drug concentration lethal to 99% of cells) = 6.1 +/- 5.4 microm (range, 1.7-21.8 microm); safingol (1-3 microm) synergistically increased 4-HPR cytotoxicity and reduced the mean 4-HPR LC(99) to 3.2 +/- 1.7 microm (range, 2.0-8.0 microm; combination index < 1). 4-HPR increased ceramide species in the three cell lines tested (up to 9-fold; P < 0.05). Hypoxia (2% O(2)) reduced ceramide species increase, DeltaPsi(m) loss, reactive oxygen species increase (P < 0.05), and 4-HPR cytotoxicity (P = 0.05; 4-HPR LC(99), 19.7 +/- 23.9 microm; range, 2.3-91.4). However, hypoxia affected 4-HPR + safingol cytotoxicity to a lesser extent (P = 0.04; 4-HPR LC(99), 4.9 +/- 2.3 microm; range, 2.0-8.2). Hypoxia increased AC RNA expression; the AC inhibitor NOE enhanced 4-HPR-induced ceramide species increase and cytotoxicity. The antioxidant N-acetyl-l-cysteine somewhat reduced 4-HPR cytotoxicity but did not affect ceramide species increase. We conclude the following: (a) 4-HPR was active against ESFT cell lines in vitro at concentrations achievable clinically, but activity was decreased in hypoxia; and (b) combining 4-HPR with ceramide modulators synergized 4-HPR cytotoxicity in normoxia and hypoxia.

Acetylcysteine↗

Therapy-related myelodysplasia and acute myeloid leukemia after Ewing sarcoma and primitive neuroectodermal tumor of bone: A report from the Children's Oncology Group.

This study describes the magnitude of risk of therapy-related myelodysplasia and acute myeloid leukemia (t-MDS/AML) in 578 individuals diagnosed with Ewing sarcoma and enrolled on Children's Oncology Group therapeutic protocol, INT-0091. Between 1988 and 1992, patients with or without metastatic disease were randomized to receive doxorubicin, vincristine, cyclophosphamide, and dactinomycin (regimen A) or these 4 drugs alternating with etoposide and ifosfamide (regimen B). Between 1992 and 1994, patients with metastatic disease were nonrandomly assigned to receive high-intensity therapy (regimen C: regimen B therapy with higher doses of doxorubicin, cyclophosphamide, and ifosfamide). Median age at diagnosis of Ewing sarcoma was 12 years, and median length of follow-up, 8 years. Eleven patients developed t-MDS/AML, resulting in a cumulative incidence of 2% at 5 years. While patients treated on regimens A and B were at a low risk for development of t-MDS/AML (cumulative incidence: 0.4% and 0.9% at 5 years, respectively), patients treated on regimen C were at a 16-fold increased risk of developing t-MDS/AML (cumulative incidence: 11% at 5 years), when compared with those treated on regimen A. Increasing exposure to ifosfamide from 90 to 140 g/m2, cyclophosphamide from 9.6 to 17.6 g/m2, and doxorubicin from 375 to 450 mg/m2 increased the risk of t-MDS/AML significantly.

Acute Disease↗