Expression of DNA Repair Genes in Ewing Sarcoma.

Background/Aim: Ewing sarcoma is an aggressive mesenchymal malignancy commonly affecting children and young adolescents. The molecular basis of this neoplasia is well reported with the formation of the EWSR1/FLI1 fusion gene being the most common genetic finding. However, this fusion gene has not been targeted therapeutically nor is being used as a prognostic marker. Its relevance regarding the molecular steps leading to Ewing sarcoma genesis are yet to be defined. The generation of the oncogenic EWSR1/FLI1 fusion gene, can be attributed to the simultaneous introduction of two DNA double-strand breaks (DSBs). The scope of this study is to detect any association between DNA repair deficiency and the clinicopathological aspects of Ewing's sarcoma disease. Patients and Methods: We have conducted an expression analysis of 35 patients diagnosed with Ewing sarcoma concerning the genes involved in non-homologous end joining (NHEJ) and homologous recombination (HR) repair pathways. We have analyzed the expression levels of 6 genes involved in NHEJ (XRCC4, XRCC5, XRCC6, POLλ, POLµ) and 9 genes involved in HR (RAD51, RAD52, RAD54, BRCA1, BRCA2, FANCC, FANCD, DNTM1, BRIT1) using real time PCR. Age, sex, location of primary tumor, tumor size, KI67, mitotic count, invasion of adjacent tissues and treatment were the clinicopathological parameters included in the statistical analysis. Results: Our results show that both these DNA repair pathways are deregulated in Ewing sarcoma. In addition, low expression of the xrcc4 gene has been associated with better overall survival probability (p=0.032). Conclusion: Our results, even though retrospective and in a small number of patients, highlight the importance of DSBs repair and propose a potential therapeutic target for this type of sarcoma.

A Case Series of BCOR Sarcomas With a New Splice Variant of BCOR/CCNB3 Fusion Gene.

BACKGROUND/AIM: Undifferentiated round cell sarcomas are a heterogeneous group of sarcomas. Identification of BCOR alterations, such as BCOR/CCNB3 and BCOR/MAML3 fusion genes and BCOR ITD has recently contributed in the precise diagnosis of these neoplasms, defining a new entity of the current classification of soft tissue and bone sarcomas. BCOR sarcomas share both morphological and genetic characteristics distinct from Ewing sarcomas. The scope of our study was to retrospectively identify BCOR sarcomas and find the correlations with the clinical outcome of these patients. PATIENTS AND METHODS: Histopathology and immunohistochemistry of pediatric tumor samples were combined with molecular testing (PCR) and fluorescent in situ hybridization to find BCOR sarcomas. RESULTS: We, herein, present our experience with BCOR sarcomas in a referral center of Greece. Moreover, we report in one case the detection of a variant BCOR/CCNB3 fusion not previously described. CONCLUSION: We are the first to report a splice variant of BCOR/CCNB3 which reveals the central position of BCOR in the oncogenesis of these tumors, furthermore we highlight the importance of molecular diagnostics in Ewing-like sarcomas and discuss the current treatment options for this rare entity.

A prospective study on the epidemiology and clinical significance of viral respiratory infections among pediatric oncology patients.

Respiratory infections in oncology are both common and potentially severe. However, there is still a gap in the literature, regarding the epidemiology of viral respiratory infections in children with cancer. We prospectively enrolled 224 patients, from September 2012 to August 2015. The cohort included children with hematologic or solid malignancies receiving chemotherapy, or undergoing hemopoietic stem cell transplantation, outpatients/inpatients exhibiting signs/symptoms of febrile/afebrile upper/lower respiratory infection. Viral infection was diagnosed by detection of ≥1 viruses from a sample at time of enrollment, using the CLART® PneumoVir kit (GENOMICA, Spain). Α detailed questionnaire including demographics and medical history was also completed. Samples were processed in batches, results were communicated as soon as they became available. Children recruited in whom no virus was detected composed the no virus detected group. Viral prevalence was 38.4% in children presenting with respiratory illness. A single virus was found in 30.4%, with RSV being the most frequent. Viral coinfections were detected in 8%. Children with viral infection were more likely to be febrile upon enrollment and to present with lower respiratory signs/symptoms. They had longer duration of illness and they were more likely to receive antibiotics/antifungals. Only 22% of children with influenza received oseltamivir. Mortality was low (2.7%), however, pediatric intensive care unit (PICU) admission and death were correlated with virus detection. In our study mortality was low and PICU admission was related to virus identification. Further research is needed to clarify whether antibiotics in virus-proven infection are of value and underline the importance of oseltamivir's timely administration in influenza.

Successful long-term hematological and immunological reconstitution by autologous cord blood transplantation combined with post-transplant immunosuppression in two children with severe aplastic anemia.

aUCBT is a valuable curative option in pediatric patients with refractory idiopathic SAA and no available matched sibling or unrelated donors. Experience in the use of autologous cord blood units in patients with SAA is limited and private for-profit cord blood-banking programs are controversial. We report the successful treatment of two patients with SAA, aged 15 and 24 months, with autologous cord blood combined with immunosuppression. After conditioning with 200 mg/kg cyclophosphamide and ATG, 7.5 mg/kg, 32.2 × 107 /kg, and 3.8 × 107 /kg autologous cord blood nucleated cells were infused, respectively. One of our patients underwent transplantation after failure of IST. Both patients received post-transplant immunosuppression with cyclosporine for 12 months. They remain disease-free 6 years post-transplantation.

Cranial Ewing's sarcoma in children.

Ewing's sarcoma is a highly malignant neoplasm of bones which accounts for the 10% of primary bone malignancies. Primary Ewing's sarcoma of skull vault is very rare and constitutes 1-6% of all Ewing's sarcomas. We present a case of a primary and a radiation-induced skull Ewing's sarcoma. The symptoms, neuroimaging findings and the treatment for these cases are reviewed. Both children were operated with favorable outcome.

Prognostic significance of angiogenesis in relation to Ki-67, p-53, p-27, and bcl-2 expression in embryonal tumors.

AIM: We investigated the angiogenesis and density of newly formed blood vessels in embryonal tumors in relation to Ki-67, bcl-2, p-53 and p-27 expression. METHODS: Forty-five children with embryonal tumors were enrolled in the study. Forty patients had a medulloblastoma (MB) and 5 patients had atypical teratoid/rhabdoid tumor (AT/RT). RESULTS: In MB, the 5-year PFS and OS was 62.5 and 70%, respectively. Patients with Ki-67 index >50%, bcl-2 index >30% and higher density of new vessels were associated with worse survival. In the multivariate analysis, Ki-67 index was identified as a factor with independent prognostic power. In AT/RTs, high density of new vessels (>25 HRF) was observed in 3 patients and Ki-67 index over 25% was found in 4 patients. CONCLUSION: Increased Ki-67, bcl-2 and density of new vessels are of prognostic value for the disease outcome in MB.

Efficacy and safety of linezolid in immunocompromised children with cancer.

BACKGROUND: The aim of this study was to determine the safety, tolerance and efficacy of linezolid for the treatment of infections from Gram-positive bacteria in immunocompromised children with cancer. METHODS: This was a prospective non-comparative unblinded study in the Hematology/Oncology Unit over a two-year period, administering linezolid as monotherapy in children with cancer. RESULTS: Seventeen children received linezolid (30 mg/kgr: 3 i.v. per day). Mean duration of linezolid administration was 12.2 days (range, 6-38 days), while the median age of the evaluable patients was 2.2 years (range, 6 months-11.2 years). Primary diagnosis was acute lymphoblastic leukemia (nine patients), brain tumor (three patients), multi-organ Langerhans cell histiocytosis (two patients), rhabdomyosarcoma, Burkitt's lymphoma and ovarian tumor (one patient each). All patients were in the midst of chemotherapy cycles. Ten out of 17 children had positive blood cultures (methicillin-resistant Staphylococcus aureus, four patients; vancomycin-resistant Enterococcus, three patients; penicillin-resistant Streptococcus pneumoniae, three patients), while seven of the 17 had fever and vancomycin-resistant Enterococcus in stool cultures. All patients were considered clinically cured after the end of the linezolid regimen (100% efficacy). The main adverse events were thrombocytopenia grade 1-3 and anemia grade 2-3 (four and two patients, respectively). Chemotherapy-induced myelotoxicity (six patients) was not worsened during linezolid therapy. No bleeding episodes were presented. Self-limited diarrhea grade 1-2 was presented in four patients (mean duration 2 days). The total adverse event rate was 23.5%; however, there was no premature cessation of linezolid in any patient. CONCLUSIONS: Linezolid may be another effective and safe therapy to treat infections from resistant Gram-positive bacteria in immunocompromised children, even in young ages.