Ewing Sarcoma / 임상소아혈액종양

Ewing sarcoma is the second most frequently occurring malignant tumor of the bone and soft tissue in adolescents and young adults. Genetically, Ewing sarcoma is characterized by balanced chromosomal translocation in which a member of FET gene family is fused with an ETS transcription factor, with the most common fusion being EWSR1-FLI1 (85% of cases). Treatment of Ewing sarcoma is based on multidisciplinary approach (local surgery, radiotherapy and multiagent chemotherapy), which are associated with chronic late effects that may compromise quality of life of survivors. First line treatment includes combination of drugs incorporating doxorubicin, vincristine, cyclophosphamide, ifosfamide, etoposide, and dactinomycin. The beneficial role of high dose chemotherapy has been suggested in high-risk localized Ewing sarcoma patients, and the studies are being performed to investigate the role in metastatic disease. The 5-year overall survival for localized Ewing sarcoma has improved to reach 65% to 75%. But patients with metastatic disease have a 5-year survival rate of <30%, except for those with isolated pulmonary metastasis (approximately 50%). Patients with recurrent tumor have a dismal prognosis. Novel therapeutic strategies based on understanding of molecular mechanisms are needed to improve the outcome of Ewing sarcoma and to lessen the treatment-related late effects.

Clinical and pathological observation on primary pulmonary primitive neuroectodermal tumor / 医学研究生学报

Objective Primitive neuroectodermal tumor (PNET) is a rare malignant small round cell tumor .This paper aimed to study the clinical and pathological features of primary pulmonary primitive neuroectodermal tumor . Methods We collected 2 cases of primary pulmonary PNET to review the clinical and pathological features .Immunohistochemical staining was used to detect immune mark-ers, and fluorescence in situ hybridization (FISH) was applied to detect EWS translocation. Results 2 patients were aged 33 years and 17 years.Microscopically, the tumor cell was composed of single small round cells in diffusion or in distribution of sheets or beams , with scant cytoplasm , oval or spindle-shaped nucleus , high mitotic count .Irregular tumor necrosis scattered in the tumor along with visi-ble rosette structure.Immunohistochemical study showed that the tumor cells were positive for CD 99, FLI-1 and Syn, while CKpan, EMA, Desmin, CgA, TTF1, CD34 were negative.EWS/FLI1 translocations were detected positive in both the cases .2 patients died 7 months and 32 months after operation , respectively . Conclusion Primary pulmonary PNET is rare , so the selection of appropriate im-mune markers (CD99, FLI-1, Syn) and FISH for the detection of EWS translocation helps to improve the accuracy of diagnosis .

Recent Advances in the Molecular Mechanisms and Therapeutic Strategies Targeting EWS/ETS in Ewing Sarcoma Family of Tumors / 임상소아혈액종양

Most cases of Ewing sarcoma family of tumors (ESFT) display a characteristic chromosomal translocation resulting in the formation of the chimeric gene, EWS/ETS. During the past two decades, the understanding of the molecular biology of the EWS/ETS gene and its role in ESFT cases has increased remarkably, and has led to the development of new therapeutic strategies. EWS/ETS is a transcription factor composed of the EWS transactivation domain and the ETS DNA binding domain. The resulting de novo chimera, EWS/ETS, disturbs the transcription of target genes. Initially known to activate its target genes, EWS/ETS has been found to represses their transcription as well. The aberrant regulation of the transcription of this gene contributes to the cellular transformation, growth, proliferation and metastasis of ESFT. Additionally, the disordered EWS/ETS protein interacts with other protein partners in transcription or splicing, and these abnormal interactions could affect gene transcription and splicing related to ESFT formation. However, the molecular mechanism underlying the oncogenesis of EWS/ETS in ESFT cases is complex and requires additional research in order to clarify its underlying mechanisms. Drugs that target the molecular mechanisms of EWS/ETS in the manifestation of ESFT have been developed and clinical studies using these drugs have recently been performed. Encouraging results were reported and new therapies may be available for use in the near future.

Recent Advances in the Molecular Mechanisms and Therapeutic Strategies Targeting EWS/ETS in Ewing Sarcoma Family of Tumors / 임상소아혈액종양

Most cases of Ewing sarcoma family of tumors (ESFT) display a characteristic chromosomal translocation resulting in the formation of the chimeric gene, EWS/ETS. During the past two decades, the understanding of the molecular biology of the EWS/ETS gene and its role in ESFT cases has increased remarkably, and has led to the development of new therapeutic strategies. EWS/ETS is a transcription factor composed of the EWS transactivation domain and the ETS DNA binding domain. The resulting de novo chimera, EWS/ETS, disturbs the transcription of target genes. Initially known to activate its target genes, EWS/ETS has been found to represses their transcription as well. The aberrant regulation of the transcription of this gene contributes to the cellular transformation, growth, proliferation and metastasis of ESFT. Additionally, the disordered EWS/ETS protein interacts with other protein partners in transcription or splicing, and these abnormal interactions could affect gene transcription and splicing related to ESFT formation. However, the molecular mechanism underlying the oncogenesis of EWS/ETS in ESFT cases is complex and requires additional research in order to clarify its underlying mechanisms. Drugs that target the molecular mechanisms of EWS/ETS in the manifestation of ESFT have been developed and clinical studies using these drugs have recently been performed. Encouraging results were reported and new therapies may be available for use in the near future.

Desmoplastic Small Round Cell Tumor with Ovarian Involvement: A Case Report

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive neoplasm that preferentially involves the abdominal and pelvic cavities in relatively young males. We present a rare case of DSRCT arising in the ovary of a 16-year-old girl. During surgery, a 15 cm-sized huge mass was noted in the right ovary and wide spreading of the tumor was identified in the left ovary, uterine wall, and omentum and bowel wall. Histological investigation showed nests of small round cells with round nuclei and scanty eosinophilic cytoplasm accompanied with dense desmoplastic stroma. The immunohistochemistry showed that the tumor coexpressed epithelial, mesenchymal, and neuronal markers. The tumor cells ultrastructurally showed poorly developed cell junctions and occasionally showed intracytoplasmic aggregates of intermediate filaments. Molecular analysis of the tumor revealed chromosomal translocation t(11:22)(p13;q12) associated with the EWS-WT1 fusion protein. DSRCT should be included in the differential diagnosis of ovarian neoplasms in young patients.

The Cytologic Features of Desmoplastic Small Round Cell Tumor with Intranuclear Inclusions : A Case Report

Desmoplastic small round cell tumor (DSRCT) is a rare neoplasm of young adults and it is characterized by polyphenotypic differentiation. We experienced a case of abdominal DSRCT that occurred in a 19-year-old female who presented with painful swelling of her right forearm. The tumor was cytokeratin-negative and it exhibited some tumor cells with intranuclear inclusions. Molecular demonstration of EWS-WT1 fusion transcripts is particularly useful to confirm the diagnosis of DSRCT without epithelial differentiation. We report here on a case of cytokeratin-negative DSRCT that showed an unusual feature of intranuclear inclusions.

A Case of RUL Bronchopleural Fistula Occluded by Flexible Bronchoscope with Endobronchial Watanabe Spigot (EWS) / 결핵및호흡기질환

An 86 year old woman was admitted complaining of dyspnea and right pleuritic pain with a 5 week durations. A physical examination, chest X-ray, and diagnostic thoracentesis upon admission revealed findings consistent with severe pneumonia and empyema on the right lung. Despite the insertion of a chest tube and negative suction via Emersion pump, the continuous air leakage was sustained, and a bronchopleural fistula (BPF) was found on the chest-CT. A flexible bronchoscopic occlusion with an Endobronchial Watanabe Spigot (EWS) was performed after 56 days of admission. An 5 mm diameter EWS was successfully inserted into the anterior segmental bronchus of the right upper lobe by flexible bronchoscope. There was no aAir leakage detected after this procedure. The patient was discharged 30 days after the EWS occlusion.

The construction and identification of prokaryotic expression vector pQE30-EWS-FLI1 / 重庆医科大学学报

Objective:To construct Ewing's sarcoma EWS-FLI1 gene prokaryotic expression vector.Methods:The target gene of EWS-FLI1 was obtained by RT-PCR method after the total RNA was extracted from Ewing's sarcoma A673 cells.The site sequences of restrictive endonuclease SacⅠand Hind Ⅲ were introduced into the upstream and downstream of target gene respectively.The target gene fragment were cloned into pMD18-T and transformed into E.Coli JM109.Screened positive clones were confirmed by PCR,restrictive endonuclease digestion and DNA sequencing.The EWS-FLI1 gene was sequentially subcloned into prokaryotic expression vector pQE30,and the recombinant plasmid pQE30-EWS-FLI1 was confirmed by restrictive endonuclease digestion and DNA sequencing.The proteins,expressed in E.coli JM109 transformed with EWS-FLI1recombinant plasmid under IPTG induction,were characterized by SDS-PAGE and Western-blot.Results:PCR result indicated that an amplified DNA fragment was in size of 1.5 kb.Restrictive endonuclease digestion analysis indicated that the target gene was in size of 1.5 kb.DNA sequencing analysis demonstrated that sequence of target gene accorded with anticipated one.The EWS-FLI1 with a molecular weight of 54 kD was highly expressed in pQE30-EWS-FLI1.Western blot proved that the expressed product had the antigenicity of EWS-FLI1.Conclusion:The recombinant prokaryotic expression vector pQE30EWS-FLI1 is constructed successfully,which will contribute to the further research of EWS-FLI1.

Induction of Apoptosis of Ewing's Sarcoma Cells by Regulating Fusion Protein Expression

PURPOSE: Fusion genes(EWS-Fli-1 and EW.S-erg) function as transcription activators and are essential for maintaining tumorigenic properties in Ewing's sarcoma cells. Several reports have noted that Ets family transcription factors bind with CBP(CREB binding protein) in vitro. To understand the interaction of fusion proteins and CBP, we studied the CBP protein in TC135 cells expressing the EWS-Fli-1 gene. We also studied the hypothesis that downregulation of fusion gene expression may induce susceptibility to apoptosis in Ewing's sarcoma cells. METHODS: For targeting fusion proteins, we reconstructed the antisense EWS-fli-l, EWS-erg and CBP genes in pcDNA3, and transfected these genes to Ewing's sarcoma cells showing high levels of expression for Ve3 and 5838 genes. These vectors were transfected to cells by the calcium phosphate method, and transformed cells were selected using G418. We measured DNA fragments for apoptosis using FACScan. We used crystal violet staining and MTT assay to evaluate cell viability, and Western blot analysis was used to assess CBP gene expression. RESULTS: Cells transfected with antisense fusion genes Ve3 and 5838 showed inhibition of fusion protein expression. These cells also showed decreased cell viability. Susceptibility to apoptosis was induced by treatment with chemotherapeutic agents at low concentrations. Antisense CBP- transfected cells showed loss of cell viability in O.l% and 0.5% serum. This loss of cell viability was similar to the response by antisense fusion protein-transfected cells treated with chemotherapeutic agents at low concentrations. CONCLUSION: Our results suggest that fusion proteins and CBP co-regulate apoptosis in Ewing's sarcoma cells. Antisense fusion gene therapy may be an useful adjunct in combining with chemotherapeutic regimens to downregulate the expression of fusion proteins in Ewing's sarcoma.