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A Zoubek

Publications and source records attributed to A Zoubek.

At least 19 recordsLinked to original sources
PubMed1999

Cryptic exons as a source of increased diversity of Ewing tumor-associated EWS-FLI1 chimeric products.

In the Ewing family of tumors (EFT), the EWS gene is rearranged with members of the ets oncogene family. Variability in genomic breakpoint locations is the source of significant heterogeneity in fusion product structure. As a consequence of variably included exon sequences from the two partner genes, a variable amount of additional peptide sequence is inserted in between the minimal transforming domains. Some of this molecular diversity has recently been correlated with disparate clinical outcome. Here we report on cryptic exons found in the chimeric RNA of three EFT with different EWS-FLI1 fusions. In two tumors, the emergence of a cryptic exon from FLI1 intron 5 in the chimeric RNA was apparently unrelated to the genomic rearrangement that occurred in FLI1 introns 4 and 5, respectively. In one case, a novel exon was generated through the creation of an artificial splice acceptor site in FLI1 intron 6 by the genomic rearrangement that occurred in EWS intron 8. These results further extend the spectrum of molecular diversity in EFT.

Adolescent↗
PubMed1999

Prognostic impact of deletions at 1p36 and numerical aberrations in Ewing tumors.

Ewing's sarcoma, peripheral primitive neuroectodermal tumors, and Askin tumors are referred to as Ewing tumors (ETs), and are characterized by high MIC2 expression and a t(11;22)(q24;q12) or other rearrangements involving 22q12. In addition to these constant aberrations, facultative numerical and structural aberrations have been reported: gains of chromosomes 8 and 12, the unbalanced translocation t(1;16), and deletions at the short arm of chromosome 1. To evaluate the frequency and to study the biological impact of these facultative aberrations, we analyzed tumor specimens from 58 ET patients by classical cytogenetics and/or in situ hybridization techniques and compared these data with clinical parameters. Gains of chromosomes 8 and 12 were detected in 55% (32/58) and 24% (14/58) of the cases, respectively. Loss of chromosome 16 or der (16)t(1;16) chromosomes were found in 20% (10/51); deletions at 1p36 were observed in 18% (9/51) of the cases evaluated. The presence of these aberrations did not correlate with age and sex of the patients, with the location of the primary tumor or with the extent of disease at diagnosis by chi-square analysis and Fisher's exact test. Patients with tumors harboring gains of chromosome 8 showed a slightly better clinical outcome (n = 14/30, P = 0.17), whereas gains of chromosome 12 did not influence the clinical outcome (n = 7/30, P = 0.63). However, Kaplan and Meier analysis revealed that deletions at the short arm of chromosome 1 were associated with an unfavorable outcome in patients with localized disease (n = 6/22; P = 0.004).

Adolescent↗
PubMed1999

Relation of neurological marker expression and EWS gene fusion types in MIC2/CD99-positive tumors of the Ewing family.

The Ewing family of tumors (EFT) is characterized by high MIC2/CD99 expression and specific EWS/ETS gene rearrangements, resulting in different chimeric transcripts. Further division into peripheral primitive neuroectodermal tumors and Ewing's sarcoma is still debated and, in the absence of distinct morphological parameters, has been based on the reactivity with neuroglial markers (NgM). We investigated 44 EFT in terms of a possible correlation between the type of EWS chimeric transcripts and reactivity with the following NgM: polyclonal and monoclonal neuron-specific enolase (NSE), S-100, chromogranin A, synaptophysin, Leu-7, glial fibrillary acid protein, and neurofilament. EWS/Fli1 fusion type 1 was detected in 30 of 44 and type 2 in 11 of 44 tumors. Three tumors, presenting with an uncommon morphology, carried rare chimeric transcripts. Our results indicate an association of lack of NgM staining with type 1 EWS/Fli1 translocations, found in 16 of 18 tumors with no NgM expression as detectable by any of the antibodies we applied. Using the monoclonal NSE antibody, 21 of 26 tumors without NgM staining expressed type 1 EWS/FLI1chimeric RNA, whereas in the groups with 1 or more and 2 or more NgM, only 9 of 17 and 1 of 5 tumors, respectively, carried type 1 EWS/Fli1 fusion transcripts. Despite this association of increased NgM expression with a non-type 1 EWS/Fli1 gene fusion, a strict correlation between the extent of NgM expression and certain EWS fusion types was not evident. This fortifies the concept to consider EFT as a spectrum of tumors and suggests the type of EWS fusion transcripts as one, but not the only parameter influencing the extent of differentiation.

Adolescent↗
PubMed1999

Low incidence of molecular evidence for tumour in PBPC harvests from patients with high risk Ewing tumours.

Reverse transcriptase polymerase chain reaction (RT-PCR) was applied to evaluate the frequency of tumour cells in PBPC products from 15 high risk Ewing tumour (ET) patients who were treated according to EICESS 92 with high-dose chemotherapy (HDC) and stem cell rescue. Initial tumour cell contamination of the bone marrow (BM) detected by light microscopy was found in five and by RT-PCR in eight cases. RT-PCR was performed on each PBPC sample repeatedly at a sensitivity comparable to 20-100 highly EWS-Fli1 expressing tumour cells per 10 ml of fresh blood. Irrespective of the extent of BM involvement at diagnosis, all BM samples obtained before harvest were RT-PCR negative. Among 12 of 35 analysed apheresis products with single positive RT-PCR results only one sample tested reproducibly positive for tumour cell contamination in independent determinations. These preliminary data suggest that tumour cell contamination of PBPC is rarely found in patients with ET.

Adolescent↗
PubMed1999

The Ewing family of tumors and the search for the Achilles' heel.

The ideal cancer therapy would accomodate the specific biology of a tumor and be based upon understanding the mechanisms of malignancy. This vision has been the driving force in cancer research. However, the story of success in clinical cancer management is a story of empirie largely independent from progress in basic research. For the Ewing family of tumors (EFT) comprising Ewing's sarcoma and peripheral primitive neuroectodermal tumor, significant insights into the molecular basis have appeared recently. Some of last year's discoveries may have taken us closer to the identification of the Achilles' heel in this disease. The first clue has been obtained to the mechanism of chromosomal translocation, which constitutes a rate-limiting step in EFT pathogenesis. Also, researchers have progressed in understanding the control of EFT cell proliferation, differentiation, and death. A major role in these processes has been attributed to the EWS-ets gene rearrangement. Specific growth factor circuits appear to be involved in deregulated tumor cell growth. By analogy to heterologous cellular systems, it is possible to postulate an important functional role for CD99(MIC2) as it contributes to the malignant phenotype of EFT. In vitro, as well as the first in vivo, experimental evidence suggests that tumor cell expansion and spread can be counteracted by breaking these physiological pathways. Still, we are far from a tailored biological therapy of EFT. Before this goal may be achieved, we must seek further improvements and diversification of today's standard and intensified treatment regimens.

Animals↗
PubMed1999

Acute myelogenous leukemia after treatment for malignant germ cell tumors in children.

PURPOSE: To identify the long-term sequelae of therapy for malignant germ cell tumors (GCTs). PATIENTS AND METHODS: Between 1980 and 1998, 1,132 patients were prospectively enrolled onto the German nontesticular GCT studies. A total of 442 patients received chemotherapy using combinations of the drugs cisplatin, ifosfamide, etoposide, vinblastine, and bleomycin, and 174 patients were treated with a combination of chemotherapy and radiotherapy. Median follow-up duration was 38 months (range, 6 to 199 months). RESULTS: Six patients developed therapy-related acute myelogenous leukemia (t-AML). There was no t-AML among patients treated with surgery (n = 392) or radiotherapy only (n = 124). The Kaplan-Meier estimates of the cumulative incidence (at 10 years) of t-AML were 1.0% for patients treated with chemotherapy (three of 442) and 4.2% for patients treated with combined chemotherapy and radiotherapy (three of 174). Notably, four of these six patients had been treated according to a standard protocol with modest cumulative chemotherapy doses. Five patients had received less than 2 g/m(2) epipodophyllotoxins, and four patients had received less than 20 g/m(2) ifosfamide. Four patients presented with AML, two with myelodysplasia in transformation to AML. In five patients, cytogenetic aberrations were found, four of which were considered characteristic for t-AML. Four patients died despite antileukemic therapy. One patient is alive but suffered a relapse of his GCT, and one patient is alive and well. No secondary solid neoplasm was observed. CONCLUSION: In patients with AML after treatment for GCT, several pathogenetic mechanisms must be considered. AML might evolve from a malignant transformation of GCT components without any influence of the chemotherapy. On the other hand, the use of alkylators and topoisomerase II inhibitors is associated with an increased risk of t-AML. Future studies will show if the reduction of treatment intensity in the current protocol reduces the risk of secondary leukemia in these patients.

Adolescent↗
PubMed1999

EWS-FLI1 and EWS-ERG gene fusions are associated with similar clinical phenotypes in Ewing's sarcoma.

PURPOSE: There are a variety of solid tumors in which alternative chromosomal translocations generate related fusion products. In alveolar rhabdomyosarcoma and synovial sarcoma, these variant fusions have been found to have major clinical significance. We investigated whether the two alternative gene fusion products, EWS-FLI1 and EWS-ERG, define different clinical subsets within the Ewing's sarcoma family of tumors. PATIENTS AND METHODS: We selected 30 cases of Ewing's sarcoma with the EWS-ERG gene fusion and 106 cases with the EWS-FLI1 fusion. Clinical data were obtained for each case and compared with the molecular diagnostic findings. RESULTS: There were no significant clinical differences observed between the two groups in age of diagnosis, sex, metastasis at diagnosis, primary site, event-free survival, or overall survival. CONCLUSION: Differences in the C-terminal partner in the Ewing's sarcoma family gene fusions are not associated with significant phenotypic differences.

Adolescent↗
PubMed1998

Second malignancies after treatment for Ewing's sarcoma: a report of the CESS-studies.

PURPOSE: During recent years, more intensified systemic and local treatment regimens have increased the 5-year survival figures in localized Ewing's sarcoma to more than 60%. There is, however, concern about the risk of second malignancies (SM) in long-term survivors. We have analyzed the second malignancies in patients treated in the German Ewing's Sarcoma Studies CESS 81 and CESS 86. MATERIALS AND METHODS: From January 1981 through June 1991, 674 patients were registered in the two sequential multicentric Ewing's sarcoma trials CESS 81 (recruitment period 1981-1985) and CESS 86 (1986-1991). The systemic treatment in both studies consisted of a four-drug-regimen (VACA = vincristine, actinomycin D, cyclophosphamide, and adriamycin; or VAIA = vincristine, actinomycin D, ifosfamide, and adriamycin) and a total number of four courses, each lasting nine weeks, was recommended by the protocol. Local therapy in curative patients was either complete surgery (n = 162), surgery plus postoperative radiotherapy with 36-46Gy (n = 274), or definitive radiotherapy with 46-60Gy (n = 212). The median follow-up at the time of this analysis was 5.1 years, the maximum follow-up 16.5 years. RESULTS: The overall survival of all patients including metastatic patients was 55% after 5 years, 48% after 10 years, and 37% after 15 years. Eight out of 674 patients (1.2%) developed a SM. Five of these were acute myelogenic leukemias (n = 4) or MDS (n = 1), and three were sarcomas. The interval between diagnosis of Ewing's sarcoma and the diagnosis of the SM was 17-78 months for the four AMLs, 96 months for the MDS and 82-136 months for the three sarcomas. The cumulative risk of an SM was 0.7% after 5 years, 2.9% after 10 years, and 4.7% after 15 years. Out of five patients with AML/MDS, three died of rapid AML-progression, and two are living with disease. Local therapy (surgery vs. surgery plus postoperative irradiation vs. definitive radiotherapy) had no impact on the frequency of AML/MDS, but local therapy did influence the risk of secondary sarcomas. All three patients with secondary sarcomas had received radiotherapy; however, all three sarcomas were salvaged by subsequent treatment and are in clinical remission with a follow-up of 1 month, 4.3 years, and 7.5 years after the diagnosis of the secondary sarcoma. Thus far, SM contributed to less than 1 % (3/328) of all deaths in the CESS-studies. CONCLUSIONS: The risk of leukemia after treatment for Ewing's sarcoma is probably in the range of 2%. The risk of solid tumors also seems to be low within the first 10 years after treatment and remains in the range of 5 % after 15 years. In the CESS-studies, less than 1% of all deaths within the first 10 years after diagnosis were caused by SM. Effective salvage therapy for secondary sarcomas is feasible.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Quality of life and psychosocial adjustment of young patients after treatment of bone cancer.

BACKGROUND: The aim of this study was to collect information about the psychosocial situation of young patients after multimodality therapy for bone cancer. METHODS: Selection criteria for patients were ages 15-30 years, tumor localization at the extremities, and an interval of at least 1 year since the end of treatment. Of 110 patients, 60 were willing to participate. Evaluation of psychosocial quality of life included assessment of psychosocial adjustment and age-appropriate achievements as well as identification of problems typical for this patient group. RESULTS: Approximately 80% of patients revealed, at the very most, only minor psychosocial problems. They were able to adapt well to their new living conditions, although strong efforts were necessary for them to deal with problems such as restricted mobility, catching up with school, or changing jobs or job orientation. Differences between patients and control subjects emerged in the areas of marital status, independent living, and parenthood. The most recently determined levels of education and income were similar. Neither clinical data nor physical or functional sequelae affected psychosocial adjustment, with one exception: patients diagnosed in adolescence had significantly more problems, especially in the area of social well-being, than patients diagnosed in childhood or early adulthood. CONCLUSIONS: Given the limitations of this study, the findings suggest that survivors of bone cancer are not necessarily at risk of developing long term emotional or social problems and are not precluded from leading active and independent lives.

Adaptation, Psychological↗
PubMed1998

Predictive potential of testing for bone marrow involvement in Ewing tumor patients by RT-PCR: a preliminary evaluation.

EWS/ets-oncogene fusion transcripts can be detected in at least 98% of Ewing tumors [(ET) Ewing sarcoma and peripheral primitive neuroectodermal tumor] by reverse transcriptase-polymerase chain reaction (RT-PCR), thus confirming the histopathologic diagnosis. To detect minimal amounts of tumor cells in the bone marrow (BM), we used an RT-PCR assay with a high sensitivity, revealing one tumor cell in a background of 10(6) normal cells. We examined BM samples from 35 newly diagnosed ET patients (23 with localized and 12 with metastatic disease). At diagnosis, tumor cells in the BM were detected in 7/23 patients with localized disease (30%). Fifty percent of patients with isolated lung metastasis were RT-PCR positive (3/6), whereas 6/6 patients with bone metastases showed positive signals (100%). All patients with initial PCR positivity in the BM became negative during treatment. After a median follow-up of 30 months, relapses were observed in both groups of patients with localized disease (3/7 RT-PCR positive and 2/16 RT-PCR negative). The only recurrence in the group with isolated lung metastases occurred as progressive lung disease in 1 of the 2 RT-PCR-negative patients, whereas among the 6 patients with bone metastases 2 remain in complete remission. So far, RT-PCR screening for BM involvement did not allow prediction of early relapse in ET. To assess better the significance of this test in the evaluation of long-term prognosis and in monitoring the effectiveness of systemic therapy, long observation periods are warranted before it becomes a tool for treatment stratification.

Adolescent↗
PubMed1998

[Cytogenetic and molecular genetic changes in malignant primary bone tumors].

Osteosarcoma, chondrosarcoma and tumors of the Ewing group are the most frequently observed primary malignant bone tumors. In an Internet homepage recently constructed for the Orthopedic Hospital Rizzoli Bologna, Italy, these tumors have represented the majority of 4423 malignant bone tumors in the archives of this institution since 1920 (http:/(/)www.tizeta.it/rizzoli). Malignant fibrous histiocytoma, fibrosarcoma, hemangioendothelioma, malignant hemangiopericytoma and giant-cell tumors are diagnosed less frequently. Since the introduction of modern molecular and cytogenetic techniques, knowledge of genetic aberrations in malignant bone tumors has steadily increased. However, so far only for the group of Ewing tumors has a recurrent chromosomal marker, the translocation t(11;22) (q24;q12), been identified.

Bone Neoplasms↗
PubMed1998

[Ewing sarcoma. Diagnostic imaging].

Ewing's sarcoma is a highly malignant neoplasm of the bone whose origin is still uncertain. A strong relationship exists between Ewing's sarcoma and tumors of neural origin (Ewing family of tumors). Ewing's sarcoma must be distinguished from other round-cell tumors like lymphoma and neuroblastoma and also must be differentiated from osteogenic sarcomas. On plain radiographs, Ewing's sarcoma appears as a lytic or mixed lytic-sclerotic, rarely as predominantly sclerotic lesion with margins Lodwick grade III. It is located primarily in the diaphyseal and metadiaphyseal regions of the long bones of the lower extremities. A large soft tissue tumor is usually present. Magnetic resonance imaging is the imaging modality of choice to evaluate the extent of the primary lesion, to monitor the response to neoadjuvant chemotherapy and to follow up non-resected Ewing's sarcomas. Bone scintigraphy is necessary to detect skeletal metastasis, and 201thallium scanning has been shown to be sensitive in the monitoring of treatment response. Today, computed tomography is not longer used to image the tumor site; however, spiral CT of the lungs plays a central role as a staging and follow-up tool.

Bone Neoplasms↗
PubMed1998

Primary metastatic (stage IV) Ewing tumor: survival analysis of 171 patients from the EICESS studies. European Intergroup Cooperative Ewing Sarcoma Studies.

BACKGROUND: In the multicenter European Intergroup Cooperative Ewing's Sarcoma Studies, localized Ewing tumors of bone were treated by combination chemotherapy with surgery and/or radiotherapy. Patients with primary metastases (pm-pts) were treated in high risk protocols. PATIENTS AND METHODS: One hundred seventy-seven pm-pts were registered from January 1990 to December 1995, 171 were evaluable for survival analyses. Thirty-six pm-pts received myeloablative megatherapy with stem cell rescue following conventional treatment. Bilateral whole lung irradiation (WLI) was administered in 57 pm-pts with pulmonary involvement. Event-free survival (EFS) rates were estimated by Kaplan-Meier analysis. Prognostic factors were identified by log-rank statistics, Cox procedures and logistic regression. RESULTS: Eighty-nine deaths were recorded by 1 February 1997, EFS four years after diagnosis for all 171 pm-pts was 0.27. EFS for isolated lung metastases was 0.34, for bone/bone marrow (BM) metastases, 0.28, and for combined lung plus bone/BM metastases, 0.14 (P < 0.005). WLI improved outcome in case of isolated pulmonary involvement (0.40 vs. 0.19, P < 0.05). In pm-pts with combined pulmonary/skeletal metastases, intensification by megatherapy and/or WLI improved EFS from 0.00 to 0.27 (P = 0.0001). CONCLUSIONS: EFS four years after diagnosis in patients with disseminated Ewing tumors is 0.27. Whole lung irradiation and megatherapy improve outcome in subgroups of patients with disseminated Ewing tumors is 0.27. Whole lung irradiation and megatherapy improve outcome in subgroups of patients with disseminated Ewing disease.

Adolescent↗
PubMed1998

Ewing's tumors with primary lung metastases: survival analysis of 114 (European Intergroup) Cooperative Ewing's Sarcoma Studies patients.

PURPOSE: To analyze event-free survival (EFS) and prognostic factors in patients who present with Ewing's tumors (ET) of bone and synchronous pulmonary and/or pleural metastases (ppm). PATIENTS AND METHODS: Of 1,270 patients (pts) registered at the continental office of the German/European Intergroup Cooperative Ewing's Sarcoma Studies (CESS81, CESS86, EICESS92), 114 were diagnosed ET with ppm. Patients underwent neoadjuvant therapy and local treatment of the primary tumor. Whole-lung irradiation 15 to 18 Gy was applied to 75 ppm-pts. EFS and 95% confidence intervals (CIs) were estimated according to the Kaplan-Meier method, and prognostic factors were analyzed by log-rank tests and Cox and logistic regression procedures. RESULTS: On November 1, 1997, at a median time under study of 5.9 years, the 5-year EFS was 0.36 (95% CI, 0.26 to 0.46) and the 10-year EFS was 0.30 (95% CI, 0.19 to 0.41). Thirty-seven of 59 (63%) first relapses involved lung and/or pleura, and the lungs were the only site of relapse in 26 of 59 (44%) ppm-pts. Risk factors identified in univariate and multivariate tests were poor response of the primary tumor toward chemotherapy, metastatic lesions in both lungs, and treatment without additional lung irradiation. CONCLUSION: Chemotherapy response of the primary tumor is a prognostic factor in patients with ET with ppm. Strategies of treatment intensification warrant further evaluation.

Adolescent↗
PubMed1997

Among genes involved in the RB dependent cell cycle regulatory cascade, the p16 tumor suppressor gene is frequently lost in the Ewing family of tumors.

The pRB cell cycle regulatory cascade is frequently perturbed in neoplasia by overexpression of a component of the pRB-phosphorylating cyclin D1/CDK4 complex or by inactivation of pRB or the CDK4 inhibitors p16 and p15. We investigated the status and expression of p16, p15, CCND1, CDK4 and RB genes in the Ewing family of tumors. P16 loss was observed in 8 of 27 tumors (30%) and in 12 of 23 (52%) tumor cell lines from unrelated patients. There were no discrepancies in the p16 status between primary tumors and the corresponding cell lines and between cell lines established from consecutive tumor samples. p15 was codeleted in most cases but p15 mRNA was absent also in cell lines retaining the gene. In addition, posttranscriptional p16 inactivation was observed in two cases. Although no evidence for CDK4 or CCND1 amplification was obtained, expression of these genes varied considerably in the cell lines in a case specific manner. In wild-type p16 cell lines, pRB expression was lost in one case. Our data indicate that, despite the absence of cytogenetically detectable 9p21 chromosomal aberrations, p16 deletions constitute the most frequent secondary molecular aberration in Ewing tumors so far. These results are discussed in the context of the stage of disease and the clinical outcome of the patients. The potential prognostic impact of these findings remains to be further evaluated.

Cell Cycle↗
PubMed1996

All-trans retinoic acid and short-time, high-dose cytarabine in two children with acute promyelocytic leukemia.

We report on two girls, 3 and 13 years old, with acute promyelocytic leukemia (APL) who were successfully treated with all-trans retinoic acid (ATRA) 45 mg/m2/day. "Retinoic acid syndrome" was prevented with short-time treatment of high dose (4 x 1.5 g/m2) cytarabine. This regimen was well tolerated, although both children were critically ill. They achieved a complete remission confirmed by light microscopy, but reverse transcriptase polymerase chain reaction remained positive after ATRA, underlining the need of further chemotherapy.

Adolescent↗