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.

Long-term outcome, clinical course and treatment approaches of paediatric langerhans cell histiocytosis: A greek reference centre report.

AIM: Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia with diverse clinical behaviour. In this article, we studied the clinical course, management and long-term outcomes of a paediatric cohort treated by our reference centre. METHODS: We retrospectively studied 66 children with LCH, consecutively diagnosed by a Greek reference centre from 1974 to 2020. RESULTS: The patients had a median age of 3.9 (range 0.0-15.9) years, 39 and 6 patients were diagnosed with unifocal or multifocal single system disease and 14 and 7 had multisystem disease with or without risk organ involvement. No late occurrence of clinical neurodegenerative disease or diabetes insipidus were observed at a median follow-up period of 4.1 (range 0.5-27.7) years. The 10-year event-free survival and overall survival were 65.0% and 90.3% and improved significantly over a 45-year period. Survival was superior in single system than multisystem cases. BRAF V600E mutation was found in 8/14 tested patients. Reactivation occurred in 12/66 patients (18.2%); 11 achieved remission and one patient died after a second relapse. CONCLUSION: LCH survival rates significantly increased in our cohort over time. Reactivation occurred in 18.2% patients, but no late neurodegeneration was found. The prognostic value of single system disease status vs. multisystem LCH was confirmed.

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.

Expression of Stem Cell Marker Nestin and MicroRNA-21 in Meningiomas.

AIM: Meningiomas are one of the most common benign intracranial tumors, making up nearly one third of all primary intracranial tumors. The majority of meningiomas have benign histological features and total resection is associated with favourable prognosis. Atypical and malignant meningiomas are associated with increased risk of recurrence. In the present study we set out to investigate the role of nestin mRNA levels and miR-21 in meningiomas. MATERIAL AND METHODS: We studied 17 patients with meningiomas that were treated surgically in our institute. Clinical variables that were analyzed were age, sex and histology. The expression of stem cell marker nestin mRNA levels and miR-21 was investigated in tissue samples by qRT-PCR. RESULTS: Considerable levels of both miR-21 and nestin mRNA were found. Atypical and anaplastic meningiomas had higher expression of both miR-21 and nestin compared to benign tumors. Furthermore, a trend towards a positive correlation between miR-21 and nestin mRNA levels was also found. CONCLUSION: Increased miR-21 and nestin mRNA levels were found in anaplastic meningiomas, in which recurrence is common, and the role of miR-21 and Nestin in meningiomas therefore warrants further investigation.

BRAF alterations in pediatric low grade gliomas and mixed neuronal-glial tumors.

Low grade astrocytomas are the most common brain tumor in children. Recent studies have identified alterations in the BRAF serine/threonine kinase gene that result in mitogen activated protein kinase pathway activation. Herewith, we investigated the genetic changes of BRAF in pediatric low grade gliomas and their relation to pathological findings and Ki-67 proliferation index. The results showed gene fusions between KIAA1549 and BRAF in 66.7 % of tumors. The majority involved the KIAA1549-BRAF exon 16-exon 9 variant. Fusion junction between KIAA1549 exon 15 and BRAF exon 9 was found in five tumors, in which the myxoid component was the predominant. This has not been previously reported. No significant correlation was found between specific KIAA1549 and BRAF fusion junctions and Ki-67 index. All of the samples included in this study were tested for the presence of the BRAF(V600E) mutation, and no positive sample was found.

Study of genetic and epigenetic alterations in urine samples as diagnostic markers for prostate cancer.

BACKGROUND: Early diagnosis of prostate cancer and identification of new prognostic factors remain main issues in prostate cancer research. In this study, we sought to test a panel of cancer-specific markers in urine samples as an aid for early cancer diagnosis. MATERIALS AND METHODS: Sedimented urine samples of 66 candidates for needle biopsy were tested. Real time-polymerase chain reaction (RT-PCR) was applied to detect the expression of transmembrane protease serine-2 and Ets-related gene fusion (TMPRSS2-ERG), Ets-related gene (ERG), prostate cancer antigen-3 (PCA3), and serine peptidase inhibitor kazal type-1 (SPINK1) transcripts. For testing of the methylation status of Glutahione S-tranferase P (GSTP1) and Ras association domain family member-1(RASSF1A) promoter region, methylation-specific PCR (MSP-PCR) was applied. RESULTS: Among the tested parameters, the presence of TMPRSS2-ERG (OR=9.044, 95% CI=2.207-37.066, p=0.002), as well as a positive test result for PCA3 (OR=7.549, 95% CI=1,858-30,672, p=0.005) were associated with the subsequent diagnosis of prostate cancer. A multivariable logistic regression including all the significantly associated variables [prostate-specific antigen (PSA), digital rectal examination (DRE), TMPRSS2-ERG and PCA3], yielded a model with area under the receiver-operating characteristic curve (AUC) =0.894 (95% CI=0.772-1.00). CONCLUSION: A multiplexed quantitative PCR analysis on sedimented urine, in conjunction with the results of serum PSA levels and DRE, has the potential to accurately foresee subsequent needle biopsy outcomes. On the basis of the above, algorithms may be designed to guide decisions for needle biopsy.

Synchronous presentation of GISTs and other primary neoplasms: a single center experience.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are common mesenchymal neoplasms of the digestive tract and may occasionally arise within the abdomen without gastrointestinal tract connection. GISTs have recently attracted widespread interest because of the development of effective targeted molecular agents against it. While synchronous occurrence of a GIST with a tumor of different histogenesis was thought to be very rare, it is now apparent that they are more common than previously believed. PATIENTS AND METHODS: We report our experience with GISTs and also six cases of GIST coexisting with other primary neoplasms. Using immunohistochemistry and mutational analysis, a possible correlation was investigated. A review of the literature was also conducted. RESULTS: There were no significant differences in the immumohistochemical and molecular profile between single GISTs and GISTs coexisting with other tumors, nor was there any mutational correlation between GISTs and the coexistent tumors of different histogenesis regarding KIT and PDGFRA genes. CONCLUSION: Further molecular biology studies are required in order to investigate thoroughly the simultaneous development of tumors with different histotypes.