Increased risk of systemic relapses associated with bone marrow micrometastasis and circulating tumor cells in localized ewing tumor

Optimization of rhabdomyosarcoma disseminated disease assessment by flow cytometry

Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children. Circulating tumor cells in peripheral blood or disseminated to bone marrow, a concept commonly referred to as minimal residual disease (MRD), are thought to be key to the prediction of metastasis and treatment efficacy. To date, two MRD markers, MYOD and MYOGENIN, have been tested; however, MRD detection continues to be challenging mainly owing to the closeness of the detection limit and the discordance of both markers in some samples. Therefore, the addition of a third marker could be useful for more accurate MRD assessment. The PAX3 gene is expressed during embryo development in all myogenic precursor cells in the dermomyotome. As RMS cells are thought to originate from these muscle precursor cells, they are expected to be positive for PAX3. In this study, PAX3 expression was characterized in cancer cell lines and tumors, showing wide expression in RMS. Detection sensitivities by quantitative polymerase chain reaction (qPCR) of the previously proposed markers, MYOD and MYOGENIN, were similar to that of PAX3, thereby indicating the feasibility of its detection. Interestingly, the flow cytometry experiments supported the usefulness of this technique in the quantification of MRD in RMS using PAX3 as a marker. These results indicate that flow cytometry, albeit in some cases slightly less sensitive, can be considered a good approach for MRD assessment in RMS and more consistent than qPCR, especially owing to its greater specificity. Furthermore, fluorescence-activated cell sorting permits the recovery of cells, thereby providing material for further characterization of circulating or disseminated cancer cells.

Paley's multiplier method does not accurately predict adult height in children with bone sarcoma

BACKGROUND

The majority of patients with osteosarcoma and Ewing's sarcoma are diagnosed before skeletal maturity. Paley's multiplier is used for height prediction in healthy children, and has been suggested as a method to make growth predictions for children with osteosarcoma and Ewing's sarcoma when considering limb salvage options. To our knowledge, no evaluation of this method in this particular patient group has been performed, but a temporary growth deficit has been observed in children undergoing chemotherapy.

QUESTIONS/PURPOSES

We asked whether (1) Paley's formula reliably predicts growth in children who received polychemotherapy; (2) chemotherapy impairs growth velocity; and (3) final adult height is impaired in these patients.

METHODS

Retrospectively, data for 94 patients with osteosarcoma and Ewing's sarcoma were retrieved from databases of two sarcoma centers. Onset before 14 years of age in girls and 16 years in boys and a minimum followup until 18 years were required (mean, 67 months; range, 31-124 months) criteria. Exclusion criteria were the intake of growth hormones or no chemotherapy. Thirty-three patients (35%) fulfilled all inclusion criteria. Predicted adult heights were compared with actual adult height. The development of a growth deficit was evaluated for 23 children (without chemotherapy for recurrence) using age- and gender-specific standard deviation scores for height (WHO Z-scores).

RESULTS

Height prediction using Paley's method showed a high percentage of false predictions (outside ± 1 SD, 70%; outside ± 2 SD, 61%). On average, the mean total height of the patients was overestimated (2.3 cm). The median absolute error of prediction was 5.0 cm (range, -17 to 8). Patients with osteosarcoma and Ewing's sarcoma showed a significant growth impairment during polychemotherapy. A catchup phase in growth before skeletal maturity was observed in patients with osteosarcoma but not with Ewing's sarcoma.

CONCLUSIONS

Owing to its lack of reliability in this patient group, methods other than Paley's should be evaluated to predict adult height. Although limited by a small number of patients, our study results indicate a decreased adult height in patients with bone sarcoma after chemotherapy.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Instructions for Authors for complete description of levels of evidence.

Gene expression profiling of peripheral blood cells: new insights into Ewing sarcoma biology and clinical applications

Ewing sarcoma (ES) is a group of highly aggressive small round cell tumors of bone or soft tissue with high metastatic potential and low cure rate. ES tumors are associated with a rapid osteolysis and necrosis. The currently accepted clinical prognostic parameters do not accurately predict survival of high-risk patients. Moreover, neither the subtype of EWS-FLI1/ERG in the tumor, nor the detection of fusion transcripts in the peripheral blood (PB) samples, has prognostic value in ES patients. We evaluated the prevalence of circulating tumor cells (CTCs) in 34 adult ES patients. Since CTCs were confirmed in only small subset of patients, we further explored the expression profiles of PB leukocytes using a panel of genes associated with immune system status and increased tumor invasiveness. Moreover, we analyzed the alterations of the routine blood tests in the examined cohort of patients and correlated our findings with the clinical outcome. A uniform decrease in ZAP70 expression in PB cells among all ES patients, as compared to healthy individuals, was observed. Monocytosis and the abnormal expression of CDH2 and CDT2 genes in the PB cells significantly correlated with poor prognosis in ES patients. Our study supports the previously proposed hypothesis of systemic nature of ES. Based on the PB cell expression profiles, we propose a mechanism by which immune system may be involved in intensification of osteoclastogenesis and disease progression in ES patients. Moreover, we demonstrate the prognostic value of molecular PB testing at the time of routine histopathological diagnosis.

Differentially expressed miRNAs in Ewing sarcoma compared to mesenchymal stem cells: low miR-31 expression with effects on proliferation and invasion

Ewing sarcoma, the second most common bone tumor in children and young adults, is an aggressive malignancy with a strong potential to metastasize. Ewing sarcoma is characterised by translocations encoding fusion transcription factors with an EWSR1 transactivation domain fused to an ETS family DNA binding domain. microRNAs are post-transcriptional regulators of gene expression and aberrantly expressed microRNAs have been identified as tumor suppressors or oncogenes in most cancer types. To identify potential oncogenic and tumor suppressor microRNAs in Ewing sarcoma, we determined and compared the expression of 377 microRNAs in 40 Ewing sarcoma biopsies, 6 Ewing sarcoma cell lines and mesenchymal stem cells, the putative cellular origin of Ewing sarcoma, from 6 healthy donors. Of the 35 differentially expressed microRNAs identified (fold change >4 and q<0.05), 19 were higher and 16 lower expressed in Ewing sarcoma. In comparisons between Ewing sarcoma samples with EWS-FLI or EWS-ERG translocations, with differing dissemination characteristics and of primary samples and metastases no significantly differential expressed microRNAs were detected using various stringency criteria. For miR-31, the microRNA with lowest expression in comparison to mesenchymal stem cells, functional analyses were performed to determine its potential as a tumor suppressor in Ewing sarcoma. Two of four miR-31 transfected Ewing sarcoma cell lines showed a significantly reduced proliferation (19% and 33% reduction) due to increased apoptosis in one and increased length of G1-phase in the other cell line. All three tested miR-31 transfected Ewing sarcoma cell lines showed significantly reduced invasiveness (56% to 71% reduction). In summary, we identified 35 microRNAs differentially expressed in Ewing sarcoma and demonstrate that miR-31 affects proliferation and invasion of Ewing sarcoma cell lines in ex vivo assays.

Zoledronic acid inhibits pulmonary metastasis dissemination in a preclinical model of Ewing's sarcoma via inhibition of cell migration

Background

Ewing’s sarcoma (ES) is the second most frequent primitive malignant bone tumor in adolescents with a very poor prognosis for high risk patients, mainly when lung metastases are detected (overall survival <15% at 5 years). Zoledronic acid (ZA) is a potent inhibitor of bone resorption which induces osteoclast apoptosis. Our previous studies showed a strong therapeutic potential of ZA as it inhibits ES cell growth in vitro and ES primary tumor growth in vivo in a mouse model developed in bone site. However, no data are available on lung metastasis. Therefore, the aim of this study was to determine the effect of ZA on ES cell invasion and metastatic properties.

Methods

Invasion assays were performed in vitro in Boyden’s chambers covered with Matrigel. Matrix Metalloproteinase (MMP) activity was analyzed by zymography in ES cell culture supernatant. In vivo, a relevant model of spontaneous lung metastases which disseminate from primary ES tumor was induced by the orthotopic injection of 10⁶ human ES cells in the tibia medullar cavity of nude mice. The effect of ZA (50 μg/kg, 3x/week) was studied over a 4-week period. Lung metastases were observed macroscopically at autopsy and analysed by histology.

Results

ZA induced a strong inhibition of ES cell invasion, probably due to down regulation of MMP-2 and −9 activities as analyzed by zymography. In vivo, ZA inhibits the dissemination of spontaneous lung metastases from a primary ES tumor but had no effect on the growth of established lung metastases.

Conclusion

These results suggest that ZA could be used early in the treatment of ES to inhibit bone tumor growth but also to prevent the early metastatic events to the lungs.

Safety considerations for transplanting cryopreserved ovarian tissue to restore fertility in female patients who have recovered from Ewing’s sarcoma

ABSTRACT Ewing’s sarcoma (EWS) is a highly malignant cancer in children, adolescents and young adults. The chemotherapy required to treat female EWS patients may cause primary ovarian insufficiency and infertility as a side effect. Cryopreservation of ovarian tissue before the start of chemotherapy can potentially preserve fertility. When the patient has been cured and primary ovarian insufficiency has developed, transplantation of frozen/thawed ovarian tissue can restore ovarian function. The tissue is usually collected before chemotherapy is initiated, and malignant cells may contaminate the stored ovarian tissue, potentially causing recrudescence of the original cancer after transplantation. The risk of EWS metastasizing to the ovary is probably low but has not been studied in great detail. This review describes the available evidence on the risk of malignant cell contamination in the ovaries of EWS patients and presents a new case of malignant cells in an ovarian biopsy from a girl with EWS.

Tumor self-seeding by circulating tumor cells in nude mouse models of human osteosarcoma and a preliminary study of its mechanisms

PURPOSE

The purpose of this study is to determine whether and how tumor self-seeding by circulating tumor cells (CTCs) plays a role in the initiation and progression of osteosarcoma.

METHODS

Two different nude mouse models of human osteosarcoma were established for detecting tumor self-seeding by fluorescently labeled CTCs. Various tumor growth indicators were quantitated for seeded and unseeded groups. Growth mechanisms were characterized using cell proliferation assays and immunohistochemical staining. Conditioned media of primary osteosarcoma cells was characterized in a Transwell migration assay and enzyme-linked immunosorbent assay. The effect of cytokines secreted by primary tumor cells was verified by small interfering RNA and recombinant human cytokine experiments.

RESULTS

Red fluorescent protein-labeled CTCs seeded primary tumors in both models. Seeded primary tumors groups grew faster than control groups (P < 0.05), which was partially attributed to the CTCs having a higher proliferation rate and higher vascular endothelial growth factor expression after self-seeding. Conditioned media of primary osteosarcoma cells attracted CTCs, through an IL-6-dependent mechanism.

CONCLUSIONS

CTC tumor self-seeding occurs in osteosarcoma and promotes the growth of primary osteosarcoma. CTCs appear to be recruited by cytokines secreted by primary osteosarcoma cells, particularly IL-6.

Autologous hematopoietic stem cell transplantation for pediatric solid tumors

While advances in the treatment of pediatric cancers have increased cure rates, children with metastatic or recurrent solid tumors have a dismal prognosis despite initial transient responses to therapy. Autologous hematopoietic stem cell transplantation takes advantage of the steep dose-response relationship observed with many chemotherapeutic agents. While clearly demonstrated to improve outcomes in patients with metastatic neuroblastoma, autologous hematopoietic stem cell transplantation is also frequently used to treat patients with other high-risk diseases such as Ewing sarcoma, osteosarcoma, rhabdomyosarcoma, Wilms' tumor, retinoblastoma, germ cell tumors, lymphomas and brain tumors. Most published experience consists of retrospective, single-arm studies; randomized clinical trials are lacking, due in part to the rarity of pediatric cancers treatable by autologous hematopoietic stem cell transplantation. These published literature demonstrate that autologous hematopoietic stem cell transplantation results in most cases in equivalent or superior outcomes when compared with conventional therapies. However, patient heterogeneity, patient selection, graft characteristics and processing and the varied conditioning regimens are additional factors to consider. Since the inception of autologous hematopoietic stem cell transplantation, regimen-related toxicity has markedly decreased and the vast majority of treatment failures are now due to disease recurrence. Prospective clinical trials are needed to identify specific high-risk patient populations, with randomization (when possible) to compare outcomes of patients undergoing autologous hematopoietic stem cell transplantation with those receiving standard therapy. In addition, investigators need to better define the role of autologous hematopoietic stem cell transplantation in these solid tumors, particularly in combination with other therapeutic modalities such as immunotherapy and novel cell processing methodologies.

The role of high-dose therapy and autologous stem cell transplantation for pediatric bone and soft tissue sarcomas

The prognosis for children with bone and soft tissue sarcomas has significantly improved since the advent of effective multiagent chemotherapy, aggressive surgery for local disease and more precise delivery of radiotherapy doses. However, in a small proportion of patients that present with high-risk disease, long-term outcome has not substantially increased, with disease-free survival rates still in the order of 20-30%. It is therefore clear that novel therapies are needed for children with these tumors. Based on the highly chemosensitive nature of the majority of pediatric sarcomas, several small studies have been conducted to investigate the potential role of high-dose chemotherapy followed by hematopoietic stem cell reconstitution. This review will provide an overview of the current literature concerning the use of high-dose therapy with stem cell transplantation for the three main pediatric sarcomas--Ewing sarcoma, rhabdomyosarcoma and osteosarcoma.

The role of cytogenetics and molecular diagnostics in the diagnosis of soft-tissue tumors

Soft-tissue sarcomas are rare, comprising <1% of all cancer diagnoses. Yet the diversity of histological subtypes is impressive with >100 benign and malignant soft-tissue tumor entities defined. Not infrequently, these neoplasms exhibit overlapping clinicopathologic features posing significant challenges in rendering a definitive diagnosis and optimal therapy. Advances in cytogenetic and molecular science have led to the discovery of genetic events in soft-tissue tumors that have not only enriched our understanding of the underlying biology of these neoplasms but have also proven to be powerful diagnostic adjuncts and/or indicators of molecular targeted therapy. In particular, many soft-tissue tumors are characterized by recurrent chromosomal rearrangements that produce specific gene fusions. For pathologists, identification of these fusions as well as other characteristic mutational alterations aids in precise subclassification. This review will address known recurrent or tumor-specific genetic events in soft-tissue tumors and discuss the molecular approaches commonly used in clinical practice to identify them. Emphasis is placed on the role of molecular pathology in the management of soft-tissue tumors. Familiarity with these genetic events provides important ancillary testing for pathologists to include in their diagnostic armamentarium.

Biomarkers in Ewing Sarcoma: The Promise and Challenge of Personalized Medicine. A Report from the Children's Oncology Group

A goal of the COG Ewing Sarcoma (ES) Biology Committee is enabling identification of reliable biomarkers that can predict treatment response and outcome through the use of prospectively collected tissues and correlative studies in concert with COG therapeutic studies. In this report, we aim to provide a concise review of the most well-characterized prognostic biomarkers in ES, and to provide recommendations concerning design and implementation of future biomarker studies. Of particular interest and potentially high clinical relevance are studies of cell-cycle proteins, sub-clinical disease, and copy number alterations. We discuss findings of particular interest from recent biomarker studies and examine factors important to the success of identifying and validating clinically relevant biomarkers in ES. A number of promising biomarkers have demonstrated prognostic significance in numerous retrospective studies and now need to be validated prospectively in larger cohorts of equivalently treated patients. The eventual goal of refining the discovery and use of clinically relevant biomarkers is the development of patient specific ES therapeutic modalities.

Children's Oncology Group's 2013 blueprint for research: bone tumors

In the US, approximately 650 children are diagnosed with osteosarcoma and Ewing sarcoma (ES) each year. Five-year survival ranges from 65% to 75% for localized disease and <30% for patients with metastases. Recent findings include interval-compressed five drug chemotherapy improves survival with localized ES. In osteosarcoma a large international trial investigating the addition of ifosfamide/etoposide or interferon to standard therapy has completed accrual. For ES an ongoing trial explores the addition of cyclophosphamide/topotecan to interval-compressed chemotherapy. Trials planned by the Children's Oncology Group will investigate new target(s) including IGF-1R and mTOR in ES, and RANKL and GD2 in osteosarcoma.

Wnt5a promotes ewing sarcoma cell migration through upregulating CXCR4 expression

Background

As one of the malignant tumors most often affecting children and young adults, Ewing sarcoma (ES) is characterized by early metastasis contributing to unfavorable prognosis. However, the molecular mechanisms responsible for ES metastasis remain poorly understood. In this study, we aimed to explore whether Wnt5a, a putative pro-metastatic factor, plays a role in ES metastasis.

Methods

Expression of Wnt5a and CXCR4 was determined by real-time PCR or Western blot in 15 ES specimens and 4 ES cell lines, A-673, RD-ES, SK-N-MC and SK-ES-1. Expression of Wnt antagonists, SFRP1, SFRP2 and SFRP5, and some components in noncanonical Wnt pathway (p-JNK, p-cJUN and p-PKC) was also analyzed in this study. Methylation status of SFRP1, SFRP2 and SFRP5 was detected by Methylation-specific PCR (MSP). Wnt5a shRNA and pcDNA3.1 SFRP5 vector were used to abrogate Wnt5a expression and overexpress SFRP5 in ES cells, respectively.

Results

Wnt5a expression was positively correlated with CXCR4 expression in ES specimens. Levels of both Wnt5a mRNA and CXCR4 mRNA were significantly higher in specimens from ES patients with metastasis at diagnosis compared with specimens from those without metastasis. Recombinant Wnt5a enhanced CXCR4 expression in ES cells, which was accompanied by increased ES cell migration, whereas Wnt5a shRNA has opposite effects. SFRP5 was methylated and silenced in ES cells, and both recombinant SFRP5 and pcDNA3.1 SFRP5 vector suppressed CXCR4 expression as well as ES cell migration. Wnt5a shRNA and recombinant SFRP5 inhibited phosphorylation of JNK and cJUN, and JNK inhibitor also reduced CXCR4 expression and cell migration in ES cells.

Conclusions

Wnt5a increases ES cell migration via upregulating CXCR4 expression in the absence of Wnt antagonist SFRP5, suggesting that Wnt5a overexpression and SFRP5 deficiency may jointly promote ES metastasis.

Efficacy of carbon-ion radiotherapy and high-dose chemotherapy for patients with unresectable Ewing's sarcoma family of tumors

BACKGROUND

Treatment for unresectable Ewing's sarcoma family of tumors (ESFT) is a formidable challenge because of its high tendency for local and distant failure. Recently, carbon-ion radiotherapy (CIRT) has been applied to unresectable bone and soft tissue sarcoma. Additionally, high-dose chemotherapy (HDC) with stem cell rescue has been used to improve the survival of patients with relapsed ESFT. Here we report our experience with CIRT and HDC in the treatment of unresectable ESFT.

METHODS

Five unresectable ESFT patients including 4 who underwent CIRT and HDC and one who underwent CIRT from 1999-2009 were retrospectively studied. After neoadjuvant chemotherapy, CIRT was conducted at the National Institute of Radiological Sciences in Chiba as local therapy. Consecutively, we employed HDC including busulfan, melphalan, and thiotepa with stem cell rescue.

RESULTS

Two patients showed tumor shrinkage after CIRT, including 1 patient who achieved partial response. No severe acute toxicity related to CIRT was observed. Local failure was observed in only 1 patient at 22 months after CIRT. Four patients conducted HDC with stem cell rescue after CIRT and 1 patient suffered from veno-occlusive disease just after HDC. Distant failure was observed in 3 patients after completion of the treatment.

CONCLUSIONS

CIRT and HDC for unresectable ESFT patients show favorable local control, with unsatisfactory results for distant control.

Circulating tumors cells as biomarkers: progress toward biomarker qualification

Personalized cancer medicine requires the development of tumor-specific biomarkers to optimize selection of targeted therapies and to better assess response to therapy. Current efforts in several tumor types have shown that patients in whom circulating tumor cells (CTCs) are detected have an inferior prognosis relative to those in whom CTCs are not detected and that the elimination or decrease of CTCs following treatment is associated with improved clinical outcomes. Technological advances in the detection, isolation, capture, and characterization of CTCs from phlebotomy samples obtained in a routine clinical practice setting have enabled the evaluation of different CTC biomarkers. Unmet needs in cancer diagnosis and treatment where CTC biomarkers have been studied include determining prognosis, assessing the effects of treatment, and as a source of tumor for the biologic identification and characterization of determinants to predict sensitivity to one form of treatment versus another and to understand mechanisms of treatment resistance.At present, there is no single definition of a CTC and no single CTC "biomarker." Rather, multiple assays (tests) are in development for CTC biomarkers. However, before the role of any biomarker in medical decision making can be determined, it is essential that the assays used to measure the biomarker are analytically validated in a sequence of trials to generate the evidence to support the biomarker's use in the given context of use. It is against this background that this review focuses on the process of developing CTC biomarker assays, with the objective of outlining the necessary steps to qualify specific CTC tests for medical decision making in clinical practice or drug development. The potential for point-of-care tests is clear.

Assessment of minimal residual disease in ewing sarcoma

Advances in molecular pathology now allow for identification of rare tumor cells in cancer patients. Identification of this minimal residual disease is particularly relevant for Ewing sarcoma, given the potential for recurrence even after complete remission is achieved. Using RT-PCR to detect specific tumor-associated fusion transcripts, otherwise occult tumor cells are found in blood or bone marrow in 20–30% of Ewing sarcoma patients, and their presence is associated with inferior outcomes. Although RT-PCR has excellent sensitivity and specificity for identifying tumor cells, technical challenges may limit its widespread applicability. The use of flow cytometry to identify tumor-specific antigens is a recently described method that may circumvent these difficulties. In this manuscript, we compare the advantages and drawbacks of these approaches, present data on a third method using fluorescent in situ hybridization, and discuss issues affecting the further development of these strategies.

Ewing sarcoma: clinical state-of-the-art

Ewing sarcoma, a rare malignancy of childhood and adolescence, has become a model of advances in diagnosis, treatment, and outcome through long-standing research efforts in multinational clinical trials. With modern multimodal regimens consisting of local surgery and/or radiotherapy plus intensive systemic chemotherapy, survival can be achieved for ≈ 70% of patients with localized disease. However, in the last decade, improvement in survival curves has slowed down. Also, a relapse rate of ≈ 30% remains unacceptable, since salvage strategies for Ewing sarcoma recurrence are discouraging and prognosis is unfavorable in most cases. Metastatic disease at diagnosis poses a similar challenge, since even if remission is achieved, relapse frequently occurs despite the most intensive treatment. Urgently needed, novel biology-driven treatment options are now beginning to emerge on the horizon, but have not yet reached the standard of care. An overview of the current clinical state-of-the-art is provided in this article.

Oxidative stress and therapeutic opportunities: focus on the Ewing's sarcoma family of tumors

Reactive oxygen species (ROS) are highly reactive by-products of energy production that can have detrimental as well as beneficial effects. Unchecked, high levels of ROS result in an imbalance of cellular redox state and oxidative stress. High levels of ROS have been detected in most cancers, where they promote tumor development and progression. Many anticancer agents work by further increasing cellular levels of ROS, to overcome the antioxidant detoxification capacity of the cancer cell and induce cell death. However, adaptation of the level of cellular antioxidants can lead to drug resistance. The challenge for the design of effective cancer therapeutics exploiting oxidative stress is to tip the cellular redox balance to induce ROS-dependent cell death but without increasing the antioxidant activity of the cancer cell or inducing toxicity in normal cells.

Treatment of Ewing sarcoma family of tumors with a modified P6 protocol in children and adolescents

BACKGROUND

Reported overall survival (OS) rates of patients with localized Ewing sarcoma family of tumors (ESFT) are >80% when treated with the MSKCC P6 protocol. However, it has been associated with a 5.8% incidence of secondary leukemias. A modified P6 (mP6) protocol with reduced exposure to chemotherapy is presented.

PROCEDURE

Thirty-one newly diagnosed ESFT patients were enrolled onto this phase II, single-arm, non-randomized protocol. Courses 1, 2 and 4 consisted of cyclophosphamide 4.2 g/m², doxorubicin 75 mg/m², and vincristine 2 mg/m² (CDV). Cycles 3 and 5 consisted of ifosfamide 9 g/m² and etoposide 500 mg/m² (IE). Course 5 ifosfamide was 14 g/m² if necrosis was <90%.

RESULTS

Twenty-four patients had loco-regional disease and seven had metastases. The 4-year event-free survival (EFS) rate for patients with localized tumors is 83% and overall survival (OS) is 92%. The 3-year EFS rate for patients with distant metastases is 28% and OS rate is 42%. EWS-FLI1 fusion genes were detected in 17 cases (74%) and EWS-ERG in six cases (26%). Type 1 EWS-FLI1 variant was present in 6/7 metastatic patients and 3/16 loco-regional cases (P = 0.001). None of the patients experienced tumor progression before remission. All relapses occurred within 2 years from the end of treatment and local relapses (n = 3) happened in patients who did not receive radiation therapy. No secondary malignancies have been observed, median follow-up of 4.3 years for surviving patients.

CONCLUSIONS

In this pilot study, the mP6 protocol produced a complete remission rate of 83% at 4 years in non-metastatic ESFT reducing the risk of secondary malignancies.

Molecular Diagnostics of Soft Tissue Tumors

Context.—Soft tissue pathology encompasses a remarkably diverse assortment of benign and malignant soft tissue tumors. Rendering a definitive diagnosis is complicated not only by the large volume of existing histologic subtypes (&gt;100) but also frequently by the presence of overlapping clinical, histologic, immunohistochemical, and/or radiographic features. During the past 3 decades, mesenchymal tumor–specific, cytogenetic and molecular genetic abnormalities have demonstrated an increasingly important, ancillary role in mesenchymal tumor diagnostics.

Objectives.—To review molecular diagnostic tools available to the pathologist to further classify specific soft tissue tumor types and recurrent aberrations frequently examined. Advantages and limitations of individual approaches will also be highlighted.

Data Sources.—Previously published review articles, peer-reviewed research publications, and the extensive cytogenetic and molecular diagnostic experience of the authors to include case files of The University of Nebraska Medical Center.

Conclusions.—Cytogenetic and molecular genetic assays are used routinely for diagnostic purposes in soft tissue pathology and represent a powerful adjunct to complement conventional microscopy and clinicoradiographic evaluation in the formulation of an accurate diagnosis. Care should be taken, however, to recognize the limitations of these approaches. Ideally, more than one technical approach should be available to a diagnostic laboratory to compensate for the shortcomings of each approach in the assessment of individual specimens.

Understanding micrometastatic disease and Anoikis resistance in ewing family of tumors and osteosarcoma

Detection of micrometastatic tumor cells in the bone marrow or peripheral blood of patients with Ewing family of tumors (EFTs) and osteosarcoma has been shown to correlate with poor outcome. Although one of the aims of chemotherapy is eradication of micrometastatic disease, these cells vary phenotypically from primary tumor cells and appear to be more resistant to chemotherapy. As a barrier to metastasis, cells normally undergo a form of cell death termed anoikis after they lose contact with the extracellular matrix or neighboring cells. Tumor cells that acquire malignant potential have developed mechanisms to resist anoikis and thereby survive after detachment from their primary site and while traveling through the circulation. Investigating mechanisms of resistance to anoikis, therefore, provides a valuable model to investigate regulation of micrometastatic disease. This review focuses on the current understanding of the mechanisms involved in mediating cell survival and resistance to anoikis in EFTs and osteosarcoma and discusses future studies that may help to identify novel therapeutics targeted at micrometastatic disease.

Ewing's sarcoma

Progress in the treatment of Ewing's sarcoma, the second most common bone tumour in children and adolescents, has improved survival from about 10% in the period before chemotherapy was introduced to about 75% today for patients with localised tumours. However, patients with metastases still fare badly, and the therapy carries short-term and long-term toxicities. Multidisciplinary care is indispensable for these patients. Molecular techniques and new imaging modalities are affecting the diagnosis and classification of patients with Ewing's sarcoma. Cooperative group studies have led to chemotherapy regimens using the same drugs (vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide), although the exact regimens differ in Europe and North America. The EWS-ETS family of gene fusions and their downstream effects in Ewing's sarcomas provide opportunities for new approaches to treatment. These include the inhibition of the fusion gene or its protein product, and pathways related to IGF1 and mTOR. Inhibition of tyrosine kinases, exploitation of non-apoptotic cell death, and interference with angiogenesis are promising new approaches. With many new approaches and relatively few patients, it will be challenging to integrate new and established treatments through clinical trials.

Ewing sarcoma family of tumors

The Ewing sarcoma family of tumors (ESFT) consists of a group of tumors characterized by morphologically similar round-cell neoplasm and by the presence of a common chromosomal translocation. Although rare, such tumors constitute the third most frequent primary sarcoma of bone after osteosarcoma and chondrosarcoma. ESFT most commonly affects young children and adolescents. Because most patients with clinically apparent localized disease at diagnosis may also have occult metastatic (ie, systemic) disease, multidrug chemotherapy as well as local disease control with surgery and/or radiation therapy are indicated for all patients. Despite marked improvements in survival during the past 40 years for patients with localized disease, lesser improvements have been seen in patients with metastatic or recurrent disease. A better understanding of the complex biology of ESFT may lead to the successful development of biologically targeted therapies. As the regulatory pathways responsible for transformation, growth, and metastasis of ESFT become more refined, the number of potential therapeutic targets will expand.

Pathology of Ewing's sarcoma/PNET: Current opinion and emerging concepts

Ewing's sarcoma/PNET are small round cell tumors showing a varying degree of neuroectodermal differentiation. They are one of the commonest tumors of childhood and occur in bone and within soft tissues. Traditionally, light microscopy with the aid of immunohistochemical stains was suitable for diagnosis. But now translocation analyses are being used not only for the diagnosis and classification of small round cell tumors, but to ascertain their prognostic significance, detect micrometastasis, and monitor minimal residual disease, with potential for targeted therapy. This article analyzes the pathology, biology, and molecular aspects of Ewing's sarcoma/PNET and discusses their clinical and therapeutic implications.

Flow cytometric detection of Ewing sarcoma cells in peripheral blood and bone marrow

BACKGROUND

A new method for detecting circulating Ewing sarcoma cells using flow cytometry is described. This strategy exploits the nearly universal expression of CD99 and the lack of expression of CD45 by Ewing sarcoma cells.

PROCEDURE

Ewing sarcoma cell line A673, peripheral blood mononuclear cells (PBMCs), and bone marrow mononuclear cells (BMMCs) were stained for CD99 and CD45 in order to detect CD99+CD45- cells by flow cytometry. Known quantities of A673 Ewing sarcoma cells were spiked into control PBMCs to test the accuracy of this method. Control PBMCs were evaluated to assess the level of background staining.

RESULTS

Flow cytometry was accurate at frequencies as low as one A673 cell per 500,000 PBMCs. The background rate of CD99+CD45- cell detection was low in PBMCs from nine healthy volunteers (median 0.0001% of total cells; range 0-0.00046%) and was further reduced by incorporating stains to exclude dead cells, progenitor cells, and monocytes. In one subject with newly diagnosed localized Ewing sarcoma, CD99+CD45- cells were detected in both blood (0.0021%) and bone marrow (0.048%).

CONCLUSIONS

Multicolor flow cytometry for CD99+CD45- cells provides a new strategy for detecting circulating Ewing sarcoma cells. Clinical evaluation and validation of this method is ongoing.

Molecular pathology of sarcomas: concepts and clinical implications

The molecular genetic changes that have been described in sarcomas over the past era have aided our understanding of their pathogenesis. The majority of sarcomas carry nonspecific genetic changes within a background of a complex karyotype. These constitute the challenges in sarcoma research for unraveling a putative multistep genetic model, such as for chondrosarcoma, and finding targets for therapeutic strategies. Approximately 15-20% of mesenchymal tumors carry a specific translocation within a relatively simple karyotype. The resulting fusion products act either as transcription factors upregulating genes responsible for tumor growth, as for instance in Ewing sarcoma, or translocate a highly active promoter in front of an oncogene driving tumor formation, as for instance in aneurysmal bone cyst. In addition, a small subset of mesenchymal tumors have specific somatic mutations driving oncogenesis. The specific genetic changes unraveled so far had great impact on the classification of bone and soft tissue tumors. In addition, these changes can assist the pathologist in the differential diagnosis of some of these entities, especially within the groups of small blue round cell tumors and spindle cell tumors, if performed in specialized centers. While a putative association between certain fusion products and outcome is still under debate, the role of predicting response of targeted therapy has been well established for KIT and PDGFRA mutations in gastrointestinal stromal tumors.

Consensus criteria for sensitive detection of minimal neuroblastoma cells in bone marrow, blood and stem cell preparations by immunocytology and QRT-PCR: recommendations by the International Neuroblastoma Risk Group Task Force

Disseminating disease is a predictive and prognostic indicator of poor outcome in children with neuroblastoma. Its accurate and sensitive assessment can facilitate optimal treatment decisions. The International Neuroblastoma Risk Group (INRG) Task Force has defined standardised methods for the determination of minimal disease (MD) by immunocytology (IC) and quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) using disialoganglioside G(D2) and tyrosine hydroxylase mRNA respectively. The INRG standard operating procedures (SOPs) define methods for collecting, processing and evaluating bone marrow (BM), peripheral blood (PB) and peripheral blood stem cell harvest by IC and QRT-PCR. Sampling PB and BM is recommended at diagnosis, before and after myeloablative therapy and at the end of treatment. Peripheral blood stem cell products should be analysed at the time of harvest. Performing MD detection according to INRG SOPs will enable laboratories throughout the world to compare their results and thus facilitate quality-controlled multi-centre prospective trials to assess the clinical significance of MD and minimal residual disease in heterogeneous patient groups.

Circulating tumor cells (CTCs): detection methods and their clinical relevance in breast cancer

The enumeration of circulating tumor cells has long been regarded as an attractive diagnostic tool, as circulating tumor cells are thought to reflect aggressiveness of the tumor and may assist in therapeutic decisions in patients with solid malignancies. However, implementation of this assay into clinical routine has been cumbersome, as a validated test was not available until recently. Circulating tumor cells are rare events which can be detected specifically only by using a combination of surface and intracellular markers, and only recently a number of technical advances have made their reliable detection possible. Most of these new techniques rely on a combination of an enrichment and a detection step. This review addresses the assays that have been described so far in the literature, including the enrichment and detection steps and the markers used in these assays. We have focused on breast cancer as most clinical studies on CTC detection so far have been done in these patients.

Molecular abnormalities in Ewing's sarcoma

Ewing's sarcoma is one of the few solid tumors for which the underlying molecular genetic abnormality has been described: rearrangement of the EWS gene on chromosome 22q12 with an ETS gene family member. These translocations define the Ewing's sarcoma family of tumors (ESFT) and provide a valuable tool for their accurate and unequivocal diagnosis. They also represent ideal targets for the development of tumor-specific therapeutics. Although secondary abnormalities occur in over 80% of primary ESFT the clinical utility of these is currently unclear. However, abnormalities in genes that regulate the G(1)/S checkpoint are frequently described and may be important in predicting outcome and response. Increased understanding of the molecular events that arise in ESFT and their role in the development and maintenance of the malignant phenotype will inform the improved stratification of patients for therapy and identify targets and pathways for the design of more effective cancer therapeutics.

Bone marrow micrometastases studied by an immunomagnetic isolation procedure in extremity localized non-metastatic osteosarcoma patients

Hematogenous spread of tumor cells is an early event in osteosarcoma and present in the majority of patients at primary diagnosis. Eradication of such micrometastases by adjuvant combination chemotherapy is crucial for survival. However, a survival plateau of 60-70% was reached over two decades ago, above which it seems difficult to further advance with the currently available therapies. In this study we have, by an immunomagnetic isolation procedure, examined the presence and prognostic impact of disseminated tumor cells in bone marrow aspirates taken at primary diagnosis in a cohort of 41 non-metastatic patients with extremity localized, high-grade osteosarcoma.

Role of prognostic factors in the management of pediatric solid tumors

The importance of prognostic factors in predicting outcome in pediatric oncology is largely recognized, and most current protocols tailor treatment based on risk stratification. Further refinements of classical staging systems are ongoing, and the future of pediatric oncology is in the development of strategies based on individual tumor characteristics. This review details significant advances in our understanding of prognostic factors in the most common pediatric solid tumors and potential applications for clinical management.

Emerging chemotherapeutic strategies and the role of treatment stratification in Ewing sarcoma

The Ewing sarcoma family of tumors (ESFT) is one of the most common groups of malignancies arising in children, adolescents, and young adults up to approximately 25 years of age. It comprises Ewing sarcoma arising from bone and extraosseous Ewing sarcoma arising from soft tissues (which includes peripheral neuroectodermal tumors and Askin tumor arising from the chest wall). Ewing sarcoma is treated successfully in many cases by a combination of chemotherapy, surgery, and radiotherapy. A number of prognostic factors have been identified that can be used to stratify patients according to the risk of relapse, allowing optimization of treatment. These can be categorized as tumor-related factors (presence of metastases, tumor site, volume, lactic dehydrogenase level, chromosomal translocation type, presence of fusion transcripts in blood and bone marrow), treatment-related factors (local therapy, histologic response to chemotherapy, radiologic response to chemotherapy, chemotherapy regimen), and patient-related factors (gender, age). Newer chemotherapeutic agents are currently being investigated, and there is now increasing interest in the identification of molecular targets in ESFT that could be exploited therapeutically, which include the mammalian target of rapamycin (mTOR) and insulin growth factor-1 (IGF-1) receptor pathways.

Clinical significance of CXC chemokine receptor-4 and c-Met in childhood rhabdomyosarcoma

PURPOSE

The CXC chemokine receptor-4 (CXCR4)/stromal-derived factor-1 and c-Met/hepatocyte growth factor axes promote the metastatic potential of rhabdomyosarcoma cell lines in experimental models, but no data are available on their role in rhabdomyosarcoma tumors. The expressions of CXCR4 and c-Met were evaluated in primary tumors and isolated tumor cells in marrow, and were correlated with clinicopathologic variables and survival.

EXPERIMENTAL DESIGN

Forty patients with recently diagnosed rhabdomyosarcoma were retrospectively enrolled. CXCR4 and c-Met expression was investigated in primary tumors by immunohistochemistry, in isolated marrow-infiltrating tumor cells using double-label immunocytology. Results were expressed as the mean percentage of immunostained tumor cells.

RESULTS

CXCR4 and c-Met were expressed in >/=5% of tumor cells from 40 of 40 tumors, with 14 of 40 cases showing >/=50% of immunostained tumor cells (high expression). High CXCR4 expression correlated with alveolar histology (P = 0.006), unfavorable primary site (P = 0.009), advanced group (P < 0.001), marrow involvement (P = 0.007), and shorter overall survival and event-free survival (P < 0.001); high c-Met expression correlated with alveolar histology (P = 0.005), advanced group (P = 0.04), and marrow involvement (P = 0.02). In patients with a positive diagnosis for isolated tumor cells in marrow (n = 16), a significant enrichment in the percentage of CXCR4-positive (P = 0.001) and c-Met-positive (P = 0.003) tumor cells was shown in marrow aspirates compared with the corresponding primary tumors.

CONCLUSIONS

CXCR4 and c-Met are widely expressed in both rhabdomyosarcoma subtypes and, at higher levels, in isolated marrow-infiltrating tumor cells. High levels of expression are associated with unfavorable clinical features, tumor marrow involvement and, only for CXCR4, poor outcome. In rhabdomyosarcoma, CXCR4 and c-Met represent novel exploitable targets for disease-directed therapy.

Ewing sarcoma and primitive neuroectodermal tumor of the esophagus: report of a case and review of literature

This study presents a case of Ewing sarcoma and primitive neuroectodermal tumor arising in the esophagus of a 44-year-old woman who presented with progressive dysphagia. Imaging studies demonstrated a polypoid lesion in the esophagus. The tumor was characterized by corded and pseudopapillary architecture, cytologic monotony, and low proliferative activity. Immunohistochemical stains were positive for CD99, neuron-specific enolase, vimentin, cyclin D1, p53, and FLI1 gene product. Fluorescence in situ hybridization demonstrated a 22q12 translocation, associated with primitive neuroectodermal tumor in the tumor cells, whereas reverse transcription polymerase chain reaction conformed expression of Ewing sarcoma/FLI1 fusion transcript in the patient's bone marrow aspirate. Although this is a rare site for this type of tumor to occur, primitive neuroectodermal tumor should be considered in the differential diagnosis of mesenchymal tumors of the esophagus. Genetic analysis is crucial to establish the diagnosis and can be successfully performed on formalin-fixed, paraffin-embedded material and hematopoietic tissue.

Novel markers of subclinical disease for Ewing family tumors from gene expression profiling

PURPOSE

Targeting subclinical disease in the bone marrow is particularly relevant in metastatic Ewing family tumors (EFT) where cure is difficult. Genome-wide expression arrays can uncover novel genes differentially expressed in tumors over normal marrow/blood, which may have potentials as markers of subclinical disease.

EXPERIMENTAL DESIGN

Gene expression array data were obtained on 28 EFT tumors using the Affymetrix U133 gene chip and compared with 10 normal blood samples. Ten genes with high tumor to blood ratios were identified. Quantitative reverse transcription-PCR was done to study (a) the dynamic range of detection of rare tumor cells, (b) the gene expression in normal blood/marrow samples, (c) the gene expression among EFT tumors, and (d) the detection and prognostic impact of marker positivity in histology-negative diagnostic marrows of EFT patients.

RESULTS

Five of 10 genes (i.e., six-transmembrane epithelial antigen of the prostate 1 [STEAP1], cyclin D1 [CCND1], NKX2-2 transcription factor [NKX2-2], plakophilin 1 [PKP1], and transmembrane protein 47 [TMEM47]) were chosen for further analyses based on their steep linear dynamic range in detecting tumor cells seeded in normal mononuclear cells and on their homogeneous expression among EFT tumors. Prognostic effect was evaluated in 35 histology-negative diagnostic marrows. Marker negativity of STEAP1, CCND1, or NKX2-2, as well as three markers in combination, was strongly correlated with patient survival as well as survival without new metastases.

CONCLUSIONS

This gene expression array-based approach identified novel markers that may be informative at diagnosis for risk group assessment. Their clinical utility needs to be tested in large patient cohorts.

Prognostic factors for local and distant control in Ewing sarcoma family of tumors

BACKGROUND

Advances in the treatment of Ewing sarcoma family of tumors (ESFT) are the result of improvements in systemic and local therapies. The individual contributions of each treatment component cannot be analyzed separately; improvements in local and systemic control can influence each other.

PATIENTS AND METHODS

We reviewed the records of 220 patients treated on institutional protocols from 1979 to 2004. Factors predictive of local and distant recurrence were analyzed.

RESULTS

The median age at diagnosis was 13.7 years. Ninety-five patients relapsed at a median of 1.6 years. The 5-year overall survival estimate was 63.5% +/- 3.5%. The estimated 5-year cumulative incidence (CI) of local failure was 25.1% +/- 3.0%. Local failure was associated with treatment era (P < 0.001), tumor size (P = 0.037) and type of local control (P = 0.021). Systemic treatment intensification improved local control. The estimated 5-year CI of distant recurrence was 22.5% +/- 2.9%. Patients with localized disease (P < 0.001), smaller tumors (P = 0.018) and those who received surgery +/- radiation for local control (P = 0.023) had lower CI of distant failure.

CONCLUSIONS

Successful treatment of ESFT requires optimal systemic and local therapy. Both treatment modalities are intertwined and the control of both local and distant disease is the result of the combined approach.

Expression of decorin, a small leucine-rich proteoglycan, as a prognostic factor in soft tissue tumors

BACKGROUND AND OBJECTIVES

Decorin is a major extracellular matrix protein which has recently become the focus of various cancer studies. However, there have so far been no reports describing the clinicopathological implications of decorin in soft tissue tumors. The aim of this study was to examine whether decorin expression is a prognostic factor in soft tissue tumors.

METHODS

Decorin expression was examined in 85 samples obtained from 77 patients by real-time quantitative PCR and immunohistochemistry.

RESULTS

Lower levels of decorin were expressed in liposarcoma and malignant peripheral nerve sheath tumor than in lipoma (<0.01) and neurofibroma (P < 0.05), respectively. An immunohistochemical analysis for spindle-cell sarcomas demonstrated decorin protein to be produced by myofibroblastic cells in the peripheral stromal extracellular spaces. On a Kaplan-Meier analysis, lower levels of decorin were associated with lower disease-free and overall survival rates (P < 0.05) in 31 spindle-cell sarcomas. A multivariate analysis revealed a significant correlation between a reduced decorin expression and a poor disease-free survival (P = 0.04). In all seven patients with recurrent or metastatic lesions, the decorin expression levels were lower in secondary lesions than in primary lesions.

CONCLUSIONS

A reduced decorin expression was found to be a useful biomarker of aggressiveness in soft tissue tumor.

Analysis of prognostic factors in ewing sarcoma family of tumors: review of St. Jude Children's Research Hospital studies

BACKGROUND

Advances in systemic and local therapies have improved outcomes for patients with the Ewing sarcoma family of tumors (ESFT). As new treatments are developed, a critical review of data from past treatment eras is needed to identify clinically relevant risk groups.

METHODS

The authors reviewed the records of 220 patients with ESFT who were treated on protocols at St. Jude Children's Research Hospital from 1979 to 2004. Two treatment eras were defined. Factors predictive of outcome were analyzed to identify distinct risk groups.

RESULTS

The median age at diagnosis was 13.7 years (range, 1.1-25.2 years). Metastatic disease was associated with tumors measuring >8 cm (P = .002) and axial location (P = .014). The 5-year overall survival (OS) estimate (63.5% +/- 3.5%) did not appear to differ by protocol. Tumor stage and size were found to be the only independent predictors of outcome. Treatment era and type of local control therapy were found to influence the outcome of patients with localized disease. Four risk groups were defined: favorable risk (age <14 years with localized, nonpelvic tumors), intermediate risk (localized, age >/=14 years, or pelvic tumors), unfavorable-pulmonary (isolated lung metastases), and unfavorable-extrapulmonary (extrapulmonary metastases). The 5-year OS estimates for these groups were 88.1% +/- 4.4%, 64.9% +/- 5.2%, 53.8% +/- 9.4%, and 27.2% +/- 7.3%, respectively (P < .001). The incidence of therapy-related leukemia was significantly higher during the second treatment era, when more intensified regimens were used (6.1% +/- 2.7% vs 0% +/- 0%; P = .005).

CONCLUSIONS

Risk stratification schemes such as this should be used to prospectively evaluate novel risk-based therapies. Studies of biologic pathways may help to refine this model.