Cross contamination meets misclassification: Awakening of CHP-100 from sleeping beauty sleep-A reviewed model for Ewing's sarcoma.

A human cell line of neuroblastic tissue, which was believed to have been lost to science due to its unavailability in public repositories, is revived and reclassified. In the 1970s, a triple set of neuroblastoma (NB) cell lines became available for research as MYCN-amplified vs nonamplified models (CHP-126/-134 and CHP-100, respectively). Confusingly, CHP-100 was used in subsequent years as a model for NB and, since the 1990s, as a model for neuroepithelioma and later as a model for Ewing's sarcoma (ES), which inevitably led to non-reproducible results. A deposit at a bioresource center revealed that globally available stocks of CHP-100 were identical to the prominent NB cell line IMR-32 and CHP-100 was included into the list of misidentified cell lines. Now we report on the rediscovery of an authentic CHP-100 cell line and provide evidence of incorrect classification during establishment. We show that CHP-100 cells carry a t(11;22)(q24;q12) type II EWSR1-FLI1 fusion and identify it as a classic ES. Although the question of whether CHP-100 was a virtual and never existing cell line from the beginning is now clarified, the results of all relevant publications should be considered questionable. Neither the time of the cross-contamination event with IMR-32 is known nor was the final classification as a model for Ewing family of tumors available with an associated short tandem repeat profile. After a long road of errors and confusion, authentic CHP-100 is now characterized as a type II EWSR1-FLI1 fusion model 44 years after its establishment.

Ewing sarcoma.

Classification of small round cell tumors of bone is often challenging due to overlapping clinicopathologic features. The purpose of this article is to review the clinical, radiological, histologic, and molecular features of Ewing sarcoma and to provide a discussion of the differential diagnosis of small round cell tumors of bone.

Extraskeletal Ewing sarcoma of the sciatic nerve.

Extraskeletal Ewing sarcoma (EES) is a rare tumor diagnosed in children or young adults and is even more unusual in individuals over 30 years of age. Due to its rare occurrence and low index of suspicion, this tumor can pose diagnostic and therapeutic challenges. We present a case of a 60-year-old male with EES of the sciatic nerve, an unexpected entity given the patient's age, tumor type, and tumor location. This can mimic a nerve sheath tumor on imaging.

Combinatorial strategies to potentiate the efficacy of HDAC inhibitors in fusion-positive sarcomas.

Fusion positive (FP) sarcomas are characterized by chromosomal rearrangements generating pathognomonic fusion transcripts and oncoproteins. In Ewing's sarcoma family of tumors (ESFTs), FP-rhabdomyosarcomas (FP-RMS) and synovial sarcomas (SS), the most common and aggressive forms of sarcomas in childhood and adolescence, the oncogenic rearrangements involve transcription cofactors causing widespread epigenetic rewiring and aberrant gene expression. Through the cooperation with histone deacetylases (HDACs) in transcription regulatory complexes, the fusion oncoproteins affect histone acetylation and chromatin remodeling. The participation of HDACs in core mechanisms of sarcoma cell transformation has paved the way to the investigation of HDAC inhibitors (HDACis) for therapeutic intervention. Preclinical studies have provided convincing evidence that HDAC activity abrogation can revert malignant cell features driven by FET-ETS, PAX3/7-FOXO1 or SS18-SSX fusion oncogenes in ESFTs, FP-RMS, or SS models, respectively, resulting in in vitro and in vivo growth inhibition. While clinical trials of HDACi monotherapies led to drug approval in some hematologic malignancies, no significant therapeutic benefit has been reported in solid tumors, including sarcomas. HDACi-based combination therapies with targeted or conventional anticancer agents have shown limited efficacy in early studies recruiting sarcoma patients, although partial responses and disease stabilization have been reported. In these trials, sarcomas were represented, however, as unclassified group in most cases. We summarize, here, studies addressing the role of HDACs in FP-sarcoma pathobiology and HDACi-based rational drug combinations. Finally, we discuss the opportunity of exploiting drug inhibitory profile and expression/function of specific HDAC isoenzymes to harness the full therapeutic potential of HDACis in these sarcoma histotypes.

Primary uterine Ewing sarcoma - A case report.

OBJECTIVE: Ewing sarcoma is a type of neuroectodermal tumors (Ewing family of tumors-EFT) that mostly affect the bone or soft tissue. Primary uterine Ewing sarcoma is extremely rare. CASE REPORT: We report a case of a primary uterine Ewing sarcoma in a 46-year-old patient, treated with total abdominal hysterectomy, and bilateral salpingo-oophorectomy and following adjuvant chemotherapy with 6 cycles of vincristine, doxorubicin, and cyclophosphamide, achieving complete remission for one year. CONCLUSION: Complete resection for EFT is the first choice of treatment, regardless of their origins. Adjuvant chemotherapy or radiotherapy is mandatory if needed. Due to rarity of the disease, this report re-emphasizes the accurate diagnosis and appropriate treatment for these unusual tumor types occurred in female genital organs.

Primary spinal multifocal intradural-extramedullary Ewing sarcoma in children: presentation of a case and review of the literature.

BACKGROUND: Primary spinal, intradural, extramedullary Ewing sarcoma (PSIEES) is exceptionally uncommon. Here, we present an interesting pediatric case with a PSIEES diagnosis confirmed by the presence of a specific fusion protein in the tumor tissue and who then developed a cerebellar recurrence. We also reviewed the PSIEES cases in childhood reported in the literature. CASE: An 8.5-year-old boy was admitted to a local hospital with a one-month history of severe back and limb pain, and inability to move his lower limbs. Physical examination revealed paraparesis in the lower extremities. Spinal MRI revealed multiple intradural extramedullary masses at the L2-L3, L4-5 and L5-S1 levels. He underwent surgery and near total excision of all three masses were performed. Histopathological diagnosis of Ewing Sarcoma was confirmed with EWS-ERG gene rearrangement. The patient was treated according to EuroEwing chemotherapy protocol. A total dose of 4500 cGy radiotherapy was applied to the tumor location at L2-S1 paravertebral region. Eighteen months after the end of treatment, a mass in the left cerebellar hemisphere was determined. Gross total excision was performed. Histopathological examination of the tumor showed Ewing sarcoma. Radiological screening revealed isolated central nervous system recurrence. A total of 4500 cGy radiotherapy was applied. He is on a second-line treatment consisting of gemcitabine and docetaxel without any evidence of disease. CONCLUSIONS: Ewing Sarcoma with spinal intradural region in childhood is very rare. We could only find 17 pediatric cases reported in the literature. Neurological findings occur earlier in tumors of this region. The prognosis is worse than other extraosseous Ewing sarcoma.

Plerixafor-aided Mobilization of Peripheral Blood Hematopoietic Stem Cells to Support Subsequent High-dose Chemotherapy After a Prior Autologous Transplant.

BACKGROUND: An appreciable proportion of patients in need of salvage high-dose chemotherapy (HDC) and autologous peripheral blood stem cell (PBSC) transplantation (PBSCT) fail to mobilize adequate numbers of hematopoietic progenitors, and plerixafor is applied for that purpose. Limited data exist on remobilization of PBSCs in patients who have relapsed after prior HDC + PBSCT. Herein, we report on consecutive patients that had undergone successful prior single or tandem HDC for a variety of malignant neoplasms in our institution, and later required re-mobilization of PBSCs in order to support further HDC cycles. PATIENTS AND METHODS: Plerixafor was administered in combination with granulocyte-colony stimulating factor alone, or after mobilizing chemotherapy. Five patients, 2 B-cell non-Hodgkin lymphomas, 1 multiple myeloma, 1 germ-cell tumor, and 1 Ewing sarcoma, having relapsed after prior HDC + PBSCT, were deemed candidates for further cycle(s) of PBSC-supported HDC. Plerixafor was applied in a "just-in-time" strategy after low CD34+ numbers were measured on the first day of anticipated hematopoietic stem cell collection (non-Hodgkin lymphoma, germ-cell tumor, and Ewing sarcoma), or pre-emptively in multiple myeloma. RESULTS: Successful collection of adequate PBSCs was achieved in all patients, from 1.8 to 3.8 × 106/kg after a median of 2 (range, 1-3) leukaphereses; 4 of 5 patients underwent subsequent HDC + PBSCT and engrafted after a median of 11 days (range, 9-55 days) and 25 days (range, 17-76 days) for neutrophils and platelets, respectively. CONCLUSION: Plerixafor proved effective to mobilize adequate numbers of PBSCs in individual patients with relapsed malignancies after prior single or tandem HDC + PBSCT. These PBSCs could establish sustained multi-lineage hematopoietic engraftment without any sequelae.

A k-mer based transcriptomics approach for antisense drug discovery targeting the Ewing's family of tumors.

Ewing's sarcoma treatment failures are associated with high mortality indicating a need for new therapeutic approaches. We used a k-mer counting approach to identify cancer-specific mRNA transcripts in 3 Ewing's Family Tumor (EFT) cell lines not found in the normal human transcriptome. Phosphorodiamidate morpholino oligomers targeting six EFT-specific transcripts were evaluated for cytotoxicity in TC-32 and CHLA-10 EFT lines and in HEK293 renal epithelial control cells. Average morpholino efficacy (EC50) was 0.66 ± 0.13 in TC-32, 0.25 ± 0.14 in CHLA-10 and 3.07 ± 5.02 µM in HEK293 control cells (ANOVA p < 0.01). Synergy was observed for a cocktail of 12 morpholinos at low dose (0.3 µM) in TC-32 cells, but not in CHLA-10 cells. Paired synergy was also observed in both EFT cell lines when the PHGDH pre-mRNA transcript was targeted in combination with XAGE1B or CYP4F22 transcripts. Antagonism was observed when CCND1 was targeted with XAGE1B or CYP4F22, or when IGFBP-2 was targeted with CCND1 or RBM11. This transcriptome profiling approach is highly effective for cancer drug discovery, as it identified new EWS-specific target genes (e.g. CYP4F22, RBM11 and IGBP-2), and predicted effective antisense agents (EC50 < 1 µM) that demonstrate both synergy and antagonism in combination therapy.

Extra-osseous Ewing sarcoma of the pancreas: case report with radiologic, pathologic, and molecular correlation, and brief review of the literature.

In 2002, due to extensive histomorphologic, immunohistochemical, and cytogenetic similarities, the World Health Organization unified undifferentiated small round blue cell neoplasms of soft tissue and bone (previously segregated as Ewing sarcoma or Primitive Neuroectodermal tumor) into one category: Ewing family of tumors (EFT). Osseous EFT are more common, and while extra-osseous EFT can occur anywhere in the body, those of the pancreas are rare and likely to be seen in the second decade of life in the head of the pancreas. We report the case of a 39-year-old Caucasian male with a large heterogeneously enhancing mass in the pancreatic body. Pathologic examination showed a malignant round blue cell tumor diffusely positive for CD99, chromogranin, and synaptophysin; Ki-67 proliferation index was greater than 80%. FISH showed EWSR1 gene rearrangement in 90% of cells and Archer FusionPlexTM-targeted RNA sequencing analysis identified the EWSR1-FLI1 fusion transcript. The diagnosis of EFT of the pancreas was rendered. Unfortunately, the patient had minimal improvement and was transitioned to oral pain medications to continue care at a different institution.

Cytopathological findings of primary pulmonary Ewing family of tumors with EWSR1 translocation: A case report.

Primary pulmonary neoplasms of the Ewing family of tumors (EFT) are extremely rare and usually occur in adolescents or young adults. Only about 40 cases of pulmonary EFT have been reported in English literature, and no cytological studies have been documented. In this report, we describe the cytopathological findings of a primary pulmonary EFT in an elderly patient. A 70-year-old man sought care because of a progressing cough and dyspnea. Chest computed tomography revealed a circumscribed mass of 6 cm in the left upper lobe. Fine needle aspiration cytology and core needle biopsy revealed uniform round cell proliferation. The predominant population consisted of cells with thickened nuclear membranes, finely dispersed chromatin, single distinct nucleoli, and indistinct cytoplasm. The other population consisted of smaller cells with darker chromatin. The cytoplasm stained positive for periodic acid-Schiff stain and was digested by diastase. Immunohistochemistry showed positivity for MIC2 (CD99), and focal positivity for neuron specific enolase, synaptophysin, and chromogranin A. Fluorescence in situ hybridization (FISH) revealed EWSR1 translocation. Although rare, pulmonary EFT cannot be disregarded, regardless of age. When two populations of uniform, round cells are observed, immunohistochemistry with MIC2 (CD99) and cytogenetic analysis by reverse transcription polymerase chain reaction or FISH should be considered. Cytological diagnosis may play an important role in the early diagnosis and treatment of pulmonary EFT.

Delayed Diagnosis of Metastatic Ewing Sarcoma Masked by Charcot-Marie-Tooth Disease.

An 18-year-old male with a history of Charcot-Marie-Tooth disease (CMT) presented with metastatic Ewing sarcoma to the lungs. He had been followed by several healthcare professionals who ascribed his enlarging 23 cm gluteal mass to his CMT. The patient experienced a significant delay in diagnosis, not uncommon in sarcoma. This case explores the various system and cognitive errors that contributed to this delay.