Peripheral primitive neuroectodermal tumor with postchemotherapy neuroblastoma-like differentiation.

We report the case of an 11-year-old girl with a retroperitoneal tumor in the left upper quadrant. The girl was admitted to hospital with weight loss and a painless abdominal mass that on biopsy was diagnosed as a peripheral primitive neuroectodermal tumor/Ewing sarcoma (pPNET/EWS) of the soft tissue. The patient underwent chemotherapy followed by surgical resection of the tumor 5 months after diagnosis. The posttreatment residual viable tumor showed a morphologic appearance resembling a neuroblastoma. Interphase and metaphase fluorescent in situ hybridization (FISH) studies performed on the pretreatment and posttreatment samples showed the presence of a t(11;22) rearrangement resulting in EWSR1/FLI1 gene fusion consistent with pPNET/EWS in both specimens. This case is unusual in the sense of showing the typical gene fusion for pPNET/EWS both in the pretherapy sample with the typical morphological appearance of this tumor and in the posttherapy specimen showing neural differentiation suggestive of a neuroblastoma.     

Translocation (4;19)(q35;q13.1)-associated primitive round cell sarcoma: report of a case and review of the literature.

We report the 4th case of a primitive round cell sarcoma with the translocation (4;19)(q35;q13.1) as the primary cytogenetic abnormality. This undifferentiated sarcoma shows some features of Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET), including a diffuse reactivity for FLI1, but it shows only focal and weak reactivity for CD99 and is negative for a rearrangement of EWS, the molecular signature of ES/PNET. Recognition of the histopathologic and cytogenetic features of this entity is necessary to avoid its misdiagnosis as ES/PNET, especially in small biopsy samples.     

Concomitant Ewing sarcoma and acute lymphoblastic leukemia in a 5-year-old girl

Malignancies from the Ewing family of tumors and acute lymphoblastic leukemia (ALL) are not known to be associated with each other. A 5-year-old girl was incidentally found to suffer from acute lymphoblastic leukemia during bone marrow staging for Ewing sarcoma of the radius. The simultaneous presence of two distinct neoplasms was confirmed by RT-PCR, with EWS/FLI1 type 1 rearrangement in the bone tumor and TEL/AML1 rearrangement in the marrow. She was treated with chemotherapy, radiotherapy, and surgery and was in remission of both diseases 31 months after diagnosis.     

Intracranial Ewing sarcoma

The occurrence of primary extraosseous Ewing sarcoma (EES) of the central nervous system (CNS) has only rarely been reported in the literature. It is important to distinguish this entity from the more common central primitive neuroectodermal tumor (PNET) of brain, since the management of these tumors is different from that of EES. We present the clinical, radiologic, and pathologic features of two cases of EES occurring in the brain. The diagnosis was further confirmed by detection of a rearrangement of the FLI1 and/or EWS gene loci in tumors from both patients using fluorescent in situ hybridization (FISH). Although rare, the possibility of EES should be considered particularly when tumors that arise near the meningeal surface of the brain and have the pathologic appearance of a PNET. Demonstration of t(11;22)(q24;q12) by molecular analysis essentially confirms the diagnosis and enables the oncologist to choose appropriate therapy.     

Evaluation of cytarabine against Ewing sarcoma xenografts by the pediatric preclinical testing program

Treatment with the nucleoside analog cytarabine has been shown to mimic changes in gene expression associated with downregulation of the EWS-FLI1 oncogene in Ewing sarcoma cell lines, selectively inhibit their growth in vitro, and cause tumor regression in athymic nude mice. For this report cytarabine was studied in vitro against a panel of 23 pediatric cancer cell lines and in vivo against 6 Ewing sarcoma xenografts. Acute lymphoblastic leukemia cell lines were the most sensitive to cytarabine in vitro (median IC(50) 9 nM), while Ewing sarcoma cell lines showed intermediate sensitivity (median IC(50) 232 nM). Cytarabine at a dose of 150 mg/kg administered daily 5× failed to significantly inhibit growth of five xenograft models, but reduced growth rate of the A673 xenograft by 50%. Cytarabine shows no differential in vitro activity against Ewing sarcoma cell lines and is ineffective in vivo against Ewing sarcoma xenografts at the dose and schedule studied.     

Reactivation of TWIST1 contributes to Ewing sarcoma metastasis

1 Background

Ewing sarcoma is a cancer of bone and soft tissue. Despite aggressive treatment, survival remains poor, particularly in patients with metastatic disease. Failure to treat Ewing sarcoma is due to the lack of understanding of the molecular pathways that regulate metastasis. In addition, no molecular prognostic markers have been identified for Ewing sarcoma to risk stratify patients.

2 Procedure

Ewing sarcoma patients were divided into high or low Twist1 gene expression and survival curves were generated using the R2 microarray‐based Genomic Analysis platform ( http://r2.amc.nl ). Tumors from Ewing sarcoma patients were also evaluated for TWIST1 expression by immunohistochemistry. Ewing sarcoma xenografts were established to evaluate the role of TWIST1 in metastasis. The effects of Twist1 on migration and invasion were evaluated using migration and invasion assays in A673 and RDES cells.

3 Results

Twist1 expression was a negative prognostic marker for overall survival in a public Ewing sarcoma patient data set based on Twist1 mRNA levels and in patient tumor samples based on Twist1 immunohistochemistry. TWIST1 is detected in significantly higher percentage of patients with metastatic diseases than localized disease. Using Ewing sarcoma tumor xenografts in mice, we found that suppressing TWIST1 levels suppressed metastasis without affecting primary tumor development. Knockdown of Twist1 inhibited the migration and invasion capability, while overexpression of Twist1 promoted migration and invasion in Ewing sarcoma cells.

4 Conclusion

These results suggest that TWIST1 promotes metastasis in Ewing sarcoma and could be used as a prognostic marker for treatment stratification; however, further validation is required in a larger cohort of patients.     

Local control of metastatic sites with radiation therapy in metastatic Ewing sarcoma and rhabdomyosarcoma

Approximately 20% of children with Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS) present with metastatic disease at initial diagnosis. Overall, the outcome is poor, with an event-free survival of < 20%. Local control at metastatic sites has not been previously reported. We reviewed control of metastatic sites in children with EWS and RMS that received curative intent radiation therapy to each metastatic site. In 13 children, at a median follow-up of 18 months, a single local failure was seen. Toxicity was minimal. Our data suggest that radiation therapy is effective and tolerable in children with metastatic EWS and RMS.     

The epidermal growth factor receptor HER2 is not a major therapeutic target in Ewing sarcoma

BACKGROUND: Although chimeric EWS gene and Ets gene fusions are pathognomonic of Ewing sarcoma (ES) and primitive neuroectodermal tumors (PNET), the molecular pathogenesis of these pediatric malignancies is poorly understood. Recently, the human epidermal growth factor (HER)-2 receptor, which plays an important role in the biology of certain epithelial cancers, has been implicated in ES tumor cell line growth and chemosensitivity. MATERIALS: To investigate whether HER2 might be a rational target for ES/PNET therapy, five ES cell lines and 13 archival primary ES/PNET samples were examined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) for evidence of HER2 overexpression. RESULTS: Although several ES cell lines demonstrated modest constitutive HER2 expression by immunoblot, none of the ES cell lines or primary tumor samples showed evidence of HER2 overexpression by IHC or HER2 gene amplification by FISH. Moreover, treatment of human ES cell lines with the HER2-targeted agent trastuzumab (Herceptin) had little effect on cell survival, proliferation, or growth in semi-solid medium. CONCLUSIONS: These results suggest that HER2 is not a biologically or therapeutically important pathway in ES/PNET.     

苦参碱联合顺铂对人肾母细胞瘤SK-NEP-1细胞PDCD4表达的影响

目的探讨苦参碱及苦参碱联合顺铂对人肾母细胞瘤SK—NEP-1细胞存活及凋亡的影响,以及可能的作用机制。方法苦参碱、顺铂单独及联合作用SK-NEP-1细胞,实验分对照组、顺铂干预组、苦参碱干预组、苦参碱联合顺铂干预组。应用四甲基偶氮唑蓝比色法检测SK-NEP-1细胞的存活率,用流式细胞仪检测其凋亡率,逆转录聚合酶链反应法检测其PDCD4mRNA的表达。结果各组SK—NEP-1细胞的存活率及凋亡率与对照组比较、相同浓度的苦参碱干预组与苦参碱联合顺铂干预组比较及苦参碱联合顺铂组与J顿铂干预组比较,SK-NEP-1细胞的存活率及凋亡率差异均有显著性（P〈0．05）。各实验组均能提高PDCD4mRNA的表达,与对照组比较,差异有显著性（P〈0．05）。苦参碱联合顺铂组与苦参碱干预组及顺铂干预组比较,SK—NEP-1细胞PDCD4mRNA表达均显著提高（P〈0．05）。结论苦参碱可浓度依赖性的抑制SK-NEP-1细胞的增殖并诱导其凋亡,从而提高对顺铂化疗的敏感性,该作用可能与提高细胞内PDCD4mRNA的表达有关。     

Differential susceptibility of pediatric sarcoma cells to oncolysis by conditionally replication-competent herpes simplex viruses

PURPOSE: Attenuated viruses derived from herpes simplex virus (HSV) type 1 that kill tumor cells (oncolysis) are currently in clinical trials for selected cancers, primarily carcinomas and gliomas. The authors sought to determine if pediatric sarcoma cells are also sensitive to HSV-mediated oncolysis. MATERIALS AND METHODS: The authors tested a panel of ten cell lines derived from rhabdomyosarcoma, osteosarcoma, Ewing sarcoma, and a secondary malignant fibrous histiocytoma for survival after exposure to attenuated HSV vectors. The viruses used included NV1020, haploid for the neurovirulence gene, and G207, deleted for both and ribonucleotide reductase but expressing the beta-galactosidase reporter gene. G207 transduction was determined by measuring beta-galactosidase expression. RESULTS: Sarcoma cells differed in their sensitivity to viral oncolysis but were relatively consistent by histologic type. Rhabdomyosarcoma and malignant fibrous histiocytoma cells were most sensitive while osteosarcoma cells were intermediately sensitive to oncolysis by both HSV recombinants. Although Ewing sarcoma cells showed efficient viral entry and gene transfer, these cells were the least susceptible to oncolysis by HSV. CONCLUSIONS: Conditionally replication-competent HSV-derived vectors may be useful for the treatment of rhabdomyosarcoma and osteosarcoma, but may not be as efficacious for treating Ewing sarcoma until the mechanism of resistance is defined and circumvented.