DMRTA2 supports glioma stem-cell mediated neovascularization in glioblastoma

Glioblastoma (GBM) is the most common and lethal brain tumor in adults. Due to its fast proliferation, diffusive growth and therapy resistance survival times are less than two years for patients with IDH-wildtype GBM. GBM is noted for the considerable cellular heterogeneity, high stemness indices and abundance of the glioma stem-like cells known to support tumor progression, therapeutic resistance and recurrence. Doublesex- and mab-3-related transcription factor a2 (DMRTA2) is involved in maintaining neural progenitor cells (NPC) in the cell cycle and its overexpression suppresses NPC differentiation. Despite the reports showing that primary GBM originates from transformed neural stem/progenitors cells, the role of DMRTA2 in gliomagenesis has not been elucidated so far. Here we show the upregulation of DMRTA2 expression in malignant gliomas. Immunohistochemical staining showed the protein concentrated in small cells with high proliferative potential and cells localized around blood vessels, where it colocalizes with pericyte-specific markers. Knock-down of DMRTA2 in human glioma cells impairs proliferation but not viability of the cells, and affects the formation of the tumor spheres, as evidenced by strong decrease in the number and size of spheres in in vitro cultures. Moreover, the knockdown of DMRTA2 in glioma spheres affects the stabilization of the glioma stem-like cell-dependent tube formation in an in vitro angiogenesis assay. We conclude that DMRTA2 is a new player in gliomagenesis and tumor neovascularization and due to its high expression in malignant gliomas could be a biomarker and potential target for new therapeutic strategies in glioblastoma.

Relevance of mutations in protein deubiquitinases genes and TP53 in corticotroph pituitary tumors

Introduction

Corticotroph pituitary neuroendocrine tumors (PitNETs) develop from ACTH-producing cells. They commonly cause Cushing's disease (CD), however, some remain clinically silent. Recurrent USP8, USP48, BRAF and TP53 mutations occur in corticotroph PitNETs. The aim of our study was to determine frequency and relevance of these mutations in a possibly large series of corticotroph PitNETs.

Methods

Study included 147 patients (100 CD and 47 silent tumors) that were screened for hot-spot mutations in USP8, USP48 and BRAF with Sanger sequencing, while 128 of these patients were screened for TP53 mutations with next generation sequencing and immunohistochemistry.

Results

USP8 mutations were found in 41% CD and 8,5% silent tumors, while USP48 mutations were found in 6% CD patients only. Both were more prevalent in women. They were related to higher rate of biochemical remission, non-invasive tumor growth, its smaller size and densely granulated histology, suggesting that these mutation may be favorable clinical features. Multivariate survival analyses did not confirm possible prognostic value of mutation in protein deubiquitinases. No BRAF mutations were found. Four TP53 mutations were identified (2 in CD, 2 in silent tumors) in tumors with size >10mm including 3 invasive ones. They were found in Crooke's cell and sparsely granulated tumors. Tumors with missense TP53 mutations had higher TP53 immunoreactivity score than wild-type tumors. Tumor with frameshift TP53 variant had low protein expression. TP53 mutation was a poor prognostic factor in CD according to uni- and multivariate survival analyses in spite of low mutations frequency.

Conclusions

We confirmed high prevalence of USP8 mutations and low incidence of USP48 and TP53 mutations. Changes in protein deubiquitinases genes appear to be favorable prognostic factors in CD. TP53 mutations are rare, occur in both functioning and silent tumors and are related to poor clinical outcome in CD.

DNA Methylation Pattern in Somatotroph Pituitary Neuroendocrine Tumors

INTRODUCTION

Growth hormone secretion by sporadic somatotroph neuroendocrine pituitary tumors (PitNETs) is a major cause of acromegaly. These tumors are relatively heterogenous in terms of histopathological and molecular features. Our previous transcriptomic profiling of somatotroph tumors revealed three distinct molecular subtypes. This study aimed to investigate the difference in DNA methylation patterns in subtypes of somatotroph PitNETs and its role in distinctive gene expression.

METHODS

Genome-wide DNA methylation was investigated in 48 somatotroph PitNETs with EPIC microarrays. Gene expression was assessed with RNAseq. Bisulfite pyrosequencing and qRT-PCR were used for verifying the results of DNA methylation and gene expression.

RESULTS

Clustering tumor samples based on methylation data reflected the transcriptome-related classification. Subtype 1 tumors are densely granulated without GNAS mutation, characterized by high expression of NR5A1 (SF-1) and GIPR. The expression of both genes is correlated with specific methylation of the gene body and promoter. This subtype has a lower methylation level of 5' gene regions and CpG islands than the remaining tumors. Subtype 2 PitNETs are densely granulated and frequently GNAS-mutated, while those in subtype 3 are mainly sparsely granulated. Methylation/expression analysis indicates that ∼50% genes located in differentially methylated regions are those differentially expressed between tumor subtypes. Correlation analysis revealed DNA methylation-controlled genes, including CDKN1B, CCND2, EBF3, CDH4, CDH12, MGMT, STAT5A, PLXND1, PTPRE, and MMP16, and genes encoding ion channels and semaphorins.

CONCLUSION

DNA methylation profiling confirmed the existence of three molecular subtypes of somatotroph PitNETs. High expression of NR5A1 and GIPR in subtype 1 tumors is correlated with specific methylation of both genes.

Epigenetic Downregulation of Hsa-miR-193b-3p Increases Cyclin D1 Expression Level and Cell Proliferation in Human Meningiomas

Meningiomas are common intracranial tumors in adults. Abnormal microRNA (miRNA) expression plays a role in their pathogenesis. Change in miRNA expression level can be caused by impaired epigenetic regulation of miRNA-encoding genes. We found the genomic region covering the MIR193B gene to be DNA hypermethylated in meningiomas based on analysis of genome-wide methylation (HumanMethylation450K Illumina arrays). Hypermethylation of MIR193B was also confirmed via bisulfite pyrosequencing. Both hsa-miR-193b-3p and hsa-miR-193b-5p are downregulated in meningiomas. Lower expression of hsa-miR-193b-3p and higher MIR193B methylation was observed in World Health Organization (WHO) grade (G) II/III tumors as compared to GI meningiomas. CCND1 mRNA was identified as a target of hsa-miR-193b-3p as further validated using luciferase reporter assay in IOMM-Lee meningioma cells. IOMM-Lee cells transfected with hsa-miR-193b-3p mimic showed a decreased cyclin D1 level and lower cell viability and proliferation, confirming the suppressive nature of this miRNA. Cyclin D1 protein expression (immunoreactivity) was higher in atypical than in benign meningiomas, accordingly to observations of lower hsa-miR-193b-3p levels in GII tumors. The commonly observed hypermethylation of MIR193B in meningiomas apparently contributes to the downregulation of hsa-miR-193b-3p. Since hsa-miR-193b-3p regulates proliferation of meningioma cells through negative regulation of cyclin D1 expression, it seems to be an important tumor suppressor in meningiomas.

DNA methylation, combined with RNA sequencing, provide novel insight into molecular classification of chordomas and their microenvironment

Chordomas are rare tumors of notochord remnants, occurring mainly in the sacrum and skull base. Despite of their unusually slow growth, chordomas are highly invasive and the involvement of adjacent critical structures causes treatment challenges. Due to the low incidence, the molecular pathogenesis of this entity remains largely unknown. This study aimed to investigate DNA methylation abnormalities and their impact on gene expression profiles in skull base chordomas. 32 tumor and 4 normal nucleus pulposus samples were subjected to DNA methylation and gene expression profiling with methylation microarrays and RNA sequencing. Genome-wide DNA methylation analysis revealed two distinct clusters for chordoma (termed subtypes C and I) with different patterns of aberrant DNA methylation. C Chordomas were characterized by general hypomethylation with hypermethylation of CpG islands, while I chordomas were generally hypermethylated. These differences were reflected by distinct distribution of differentially methylated probes (DMPs). Differentially methylated regions (DMRs) were identified, indicating aberrant methylation in known tumor-related genes in booth chordoma subtypes and regions encoding small RNAs in subtype C chordomas. Correlation between methylation and expression was observed in a minority of genes. Upregulation of TBXT in chordomas appeared to be related to lower methylation of tumor-specific DMR in gene promoter. Gene expression-based clusters of tumor samples did not overlap with DNA methylation-based subtypes. Nevertheless, they differ in transcriptomic profile that shows immune infiltration in I chordomas and up-regulation of cell cycle in C chordomas. Immune enrichment in chordomas I was confirmed with 3 independent deconvolution methods and immunohistochemistry. Copy number analysis showed higher chromosomal instability in C chordomas. Nine out of eight had deletion of CDKN2A/B loci and downregulation of genes encoded in related chromosomal band. No significant difference in patients' survival was observed between tumor subtypes, however, shorter survival was observed in patients with higher number of copy number alterations.

Targeted sequencing of cancer-related genes reveals a recurrent TOP2A variant which affects DNA binding and coincides with global transcriptional changes in glioblastoma

High-grade gliomas are aggressive, deadly primary brain tumors. Median survival of patients with glioblastoma (GBM, WHO grade 4) is 14 months and <10% of patients survive 2 years. Despite improved surgical strategies and forceful radiotherapy and chemotherapy, the prognosis of GBM patients is poor and did not improve over decades. We performed targeted next-generation sequencing with a custom panel of 664 cancer- and epigenetics-related genes, and searched for somatic and germline variants in 180 gliomas of different WHO grades. Herein, we focus on 135 GBM IDH-wild type samples. In parallel, mRNA sequencing was accomplished to detect transcriptomic abnormalities. We present the genomic alterations in high-grade gliomas and the associated transcriptomic patterns. Computational analyses and biochemical assays showed the influence of TOP2A variants on enzyme activities. In 4/135 IDH-wild type GBMs we found a novel, recurrent mutation in the TOP2A gene encoding topoisomerase 2A (allele frequency [AF] = 0.03, 4/135 samples). Biochemical assays with recombinant, wild type (WT) and variant proteins demonstrated stronger DNA binding and relaxation activity of the variant protein. GBM patients carrying the altered TOP2A had shorter overall survival (median OS 150 vs 500 days, P = .0018). In the GBMs with the TOP2A variant we found transcriptomic alterations consistent with splicing dysregulation. luA novel, recurrent TOP2A mutation, which was found exclusively in four GBMs, results in the TOP2A E948Q variant with altered DNA binding and relaxation activities. The deleterious TOP2A mutation resulting in transcription deregulation in GBMs may contribute to disease pathology.

The expression of glucocorticoid and mineralocorticoid receptors in pituitary tumors causing Cushing's disease and silent corticotroph tumors

OBJECTIVE

Pituitary neuroendocrine corticotroph tumors commonly cause Cushing's disease (CD) that results from increased adrenocorticotropic hormone (ACTH) secretion by the pituitary tumor and consequent increase of cortisol levels in blood. However, in some patients, corticotroph tumors remain clinically non-functioning. Cortisol secretion is regulated by the hypothalamic-pituitary-adrenal axis and includes a negative feedback between cortisol and ACTH secretion. Glucocorticoids reduce ACTH level both by hypothalamic regulation and acting on corticotrophs via glucocorticoid (GR) and mineralocorticoid (MR) receptors. The aim of the study was to determine the role of GR and MR expression at mRNA and protein levels in both functioning and silent corticotroph tumors.

METHODS

Ninety-five patients were enrolled, including 70 with CD and 25 with silent corticotroph tumors. Gene expression levels of NR3C1 and NR3C2 coding for GR and MR, respectively, were determined with qRT-PCR in the two tumor types. GR and MR protein abundance was assessed with immunohistochemistry.

RESULTS

Both GR and MR were expressed in corticotroph tumors. Correlation between NR3C1 and NR3C2 expression levels was observed. NR3C1 expression was higher in silent than in functioning tumors. In CD patients NR3C1 and NR3C2 levels were negatively correlated with morning plasma ACTH levels and tumor size. Higher NR3C2 was confirmed in patients with remission after surgery and in densely granulated tumors. Expression of both genes and GR protein was higher in USP8-mutated tumors. Similar relationship between USP8 mutations and expression levels were observed in analysis of silent tumors that also revealed a negative correlation between GR and tumor size and higher NR3C1 expression in densely granulated tumors.

CONCLUSIONS

Although the associations between gene/protein expression and patients clinical features are not strong, they consistently show an evident trend in which higher receptor expression corresponds to more favorable clinical characteristics.

The Expression of Cell Cycle-Related Genes in USP8-Mutated Corticotroph Neuroendocrine Pituitary Tumors and Their Possible Role in Cell Cycle-Targeting Treatment

Protein deubiquitinases USP8 and USP48 are known driver genes in corticotroph pituitary neuroendocrine tumors (PitNETs). USP8 mutations have pleiotropic effects that include notable changes in genes' expression. Genes involved in cell cycle regulation were found differentially expressed in mutated and wild-type tumors. This study aimed to verify difference in the expression level of selected cell cycle-related genes and investigate their potential role in response to cell cycle inhibitors. Analysis of 70 corticotroph PitNETs showed that USP8-mutated tumors have lower CDKN1B, CDK6, CCND2 and higher CDC25A expression. USP48-mutated tumors have lower CDKN1B and CCND1 expression. A lower p27 protein level in mutated than in wild-type tumors was confirmed that may potentially influence the response to small molecule inhibitors targeting the cell cycle. We looked for the role of USP8 mutations or a changed p27 level in the response to palbociclib, flavopiridol and roscovitine in vitro using murine corticotroph AtT-20/D16v-F2 cells. The cells were sensitive to each agent and treatment influenced the expression of genes involved in cell cycle regulation. Overexpression of mutated Usp8 in the cells did not affect the expression of p27 nor the response to the inhibitors. Downregulating or upregulating p27 expression in AtT-20/D16v-F2 cells also did not affect treatment response.

Circulating Hsa-miR-431-5p as Potential Biomarker for Squamous Cell Vulvar Carcinoma and Its Premalignant Lesions

Vulvar squamous cell carcinoma (VSCC) develops from high-grade squamous intraepithelial lesions (HSIL) and differentiated vulvar intraepithelial neoplasia (dVIN). This study aimed to assess the diagnostic value of circulating hsa-miR-431-5p in vulvar precancers and VSCC. Expression levels of hsa-miR-431-5p were analyzed by quantitative RT-PCR in plasma samples of 29 patients with vulvar precancers (HSIL or dVIN), 107 with VSCC as well as 15 healthy blood donors. We used hsa-miR-93-5p and hsa-miR-425-5p as normalizers. The levels of miR-431-5p were increased in the blood of patients with VSCC compared to those with vulvar precancers. Statistically significant differences in the survival rates (time to progression) were revealed for VSCC patients categorized by miR-431-5p levels. Low levels of circulating miR-431-5p were found to be indicative of unfavorable survival rates. In summary, our data reveal the diagnostic potential of circulating miR-431-5p in patients with vulvar precancers and VSCC.

ECOA-6. Genomic and transcriptomic analyses reveal diverse mechanisms responsible for deregulation of epigenetic enzyme/modifier expression in glioblastoma

Malignant gliomas represent over 70% of primary brain tumors and the most deadly is glioblastoma (GBM, WHO grade IV), due to frequent dysfunctions of tumor suppressors or/and oncogenes. Recent whole genome studies of gliomas demonstrated that besides genetic alterations, epigenetic dysfunctions contribute to tumor development and progression. Alterations in genes encoding epigenetic enzyme/protein or aberrations in epigenetic modification pattern have been found in gliomas of lower grade, yet no epigenetic driver was identified in GBM. We sought to identify different mechanisms driving aberrant expression of epigenetic genes in GBM.

We analyzed gene expression and coding/non-coding regions of 96 major epigenetic enzymes and chromatin modifiers in 28 GBMs, 23 benign gliomas (juvenile pilocytic astrocytomas, JPAs, WHO grade I) and 7 normal brain samples. We found a profound and global down-regulation of expression of most tested epigenetic enzymes and modifiers in GBMs when compared to normal brains and JPAs. For some genes changes in mRNA level correlated with newly identified single nucleotide variants within non-coding regulatory regions. To find a common denominator responsible for the coordinated down-regulation of expression of epigenetic enzymes/modifiers, we employed PWMEnrich tool for DNA motif scanning and enrichment analysis. Among others, we discovered the presence of high affinity motifs for the E2F1/E2F4 transcription factors, within the promoters of the epigenetic enzyme/modifier encoding genes. Knockdown of the E2F1/E2F4 expression affected the expression of a set of epigenetic enzymes/modifiers. Altogether, our results reveal a novel epigenetic-related pathway by which E2F1/E2F4 factors contribute to glioma pathogenesis and indicate novel targets for glioma therapy.

Supported by a National Science Centre grant 2013/09/B/NZ3/01402 (MM).

Invasive and Noninvasive Nonfunctioning Gonadotroph Pituitary Tumors Differ in DNA Methylation Level of LINE-1 Repetitive Elements

PURPOSE

Epigenetic dysregulation plays a role in pituitary tumor pathogenesis. Some differences in DNA methylation were observed between invasive and noninvasive nonfunctioning gonadotroph tumors. This study sought to determine the role of DNA methylation changes in repetitive LINE-1 elements in nonfunctioning gonadotroph pituitary tumors.

METHODS

We investigated LINE-1 methylation levels in 80 tumors and normal pituitary glands with bisulfite-pyrosequencing. Expression of two LINE-1 open reading frames (L1-ORF1 and L1-ORF2) was analyzed with qRT-PCR in tumor samples and mouse gonadotroph pituitary cells treated with DNA methyltransferase inhibitor. Immunohistochemical staining against L1-ORF1p was also performed in normal pituitary glands and tumors.

RESULTS

Hypomethylation of LINE-1 was observed in pituitary tumors. Tumors characterized by invasive growth revealed lower LINE-1 methylation level than noninvasive ones. LINE-1 methylation correlated with overall DNA methylation assessed with HM450K arrays and negatively correlated with L1-ORF1 and L1-ORF2 expression. Treatment of αT3-1 gonadotroph cells with 5-Azacytidine clearly increased the level of L1-ORF1 and L1-ORF2 mRNA; however, its effect on LβT2 cells was less pronounced. Immunoreactivity against L1-ORF1p was higher in tumors than normal tissue. No difference in L1-ORF1p expression was observed in invasive and noninvasive tumors.

CONCLUSION

Hypomethylation of LINE-1 is related to invasive growth and influences transcriptional activity of transposable elements.

DNA Methylation Influences miRNA Expression in Gonadotroph Pituitary Tumors

microRNAs are involved in pathogenesis of cancer. DNA methylation plays a role in transcription of miRNA-encoding genes and may contribute to changed miRNA expression in tumors. This issue was not investigated in pituitary neuroendocrine tumors (PitNETs) previously. DNA methylation patterns, assessed with HumanMethylation450K arrays in 34 PitNETs and five normal pituitaries, were used to determine differentially methylated CpGs located at miRNA genes. It showed aberrant methylation in regions encoding for 131 miRNAs. DNA methylation data and matched miRNA expression profiles, determined with next-generation sequencing (NGS) of small RNAs, were correlated in 15 PitNETs. This showed relationship between methylation and expression levels for 12 miRNAs. DNA methylation and expression levels of three of them (MIR145, MIR21, and MIR184) were determined in the independent group of 80 tumors with pyrosequencing and qRT-PCR and results confirmed both aberrant methylation in PitNETs and correlation between methylation and expression. Additionally, in silico target prediction was combined with analysis of established miRNA profiles and matched mRNA expression pattern, assessed with amplicon-based NGS to indicate putative target genes of epigenetically deregulated miRNAs. This study reveals aberrant DNA methylation in miRNA-encoding genes in gonadotroph PitNETs. Methylation changes affect expression level of miRNAs that regulate putative target genes with tumorigenesis-relevant functions.

The Search of miRNA Related to Invasive Growth of Nonfunctioning Gonadotropic Pituitary Tumors

PURPOSE

Nonfunctioning gonadotropic pituitary neuroendocrine tumors (PitNETs) are among the most frequent neoplasms of pituitary gland. Although PitNETs are commonly considered benign, a notable part of patients suffer from tumor recurrence after treatment. Invasive growth of pituitary tumor is among the most important prognostic factors. Since molecular features of invasiveness are of potential clinical usefulness, this study was aimed to verify whether invasive and noninvasive nonfunctioning gonadotropic PitNETs differ in the miRNA expression profile and whether the differences could provide a possible molecular classifier.

METHODS

miRNA profiles were determined in 20 patients (11 invasive and 9 noninvasive tumors) using next-generation sequencing. The expression of selected miRNAs was assessed in the independent cohort of 80 patients with qRT-PCR.

RESULTS

When miRNA profiles of invasive and noninvasive tumors were compared, 29 miRNAs were found differentially expressed. Hsa-miR-184, hsa-miR-181a-2-3p, hsa-miR-93-3p, hsa-miR-574-5p, hsa-miR-185-5p, and hsa-miR-3200-5p showed a potential clinical value according to ROC curve analysis. Unfortunately, differential expression of only hsa-miR-185-5p was confirmed in the validation cohort, with AUG at 0.654.

CONCLUSION

Differences in miRNAs expression profiles in invasive and noninvasive gonadotropic PitNETs are slight and the level of miRNA expression seems not to be applicable as useful classifier of tumor invasiveness.

USP8 mutations in corticotroph adenomas determine a distinct gene expression profile irrespective of functional tumour status

OBJECTIVE

Pituitary corticotroph adenomas commonly cause Cushing's disease (CD) but part of these tumours are hormonally inactive (silent corticotroph adenomas, SCA). USP8 mutations are well-known driver mutations in corticotrophinomas. Differences in transcriptomic profiles between functioning and silent tumours or tumours with different USP8 status have not been investigated.

DESIGN AND METHODS

Forty-eight patients (28 CD, 20 SCA) were screened for USP8 mutations with Sanger sequencing. Twenty-four patients were included in transcriptomic profiling with Ampliseq Transcriptome Human Gene Expression Core Panel. The entire patients group was included in qRT-PCR analysis of selected genes expression. Immunohistochemistry was used for visualization of selected protein.

RESULTS

We found USP8 mutation in 15 patients with CD and 4 SCAs. USP8 mutations determine molecular profile of the tumours as showed by hierarchical clustering and identification of 1648 genes differentially expressed in USP8-mutated and USP8-wild-type tumours. Mutations affect many molecular pathways as observed in Gene Set Enrichment analysis. USP8-mutated adenomas showed higher level of POMC, CDC25A, MAPK4 but lower level of CCND2, CDK6, CDKN1B than USP8-wt tumours. Eighty-seven genes differentially expressed between CD-related adenomas and SCAs were found, including those involved in cell signalling (GLI2, DLC1, TBX2, RASSF6), cell adhesion (GJA1, CDH6), ion transport (KCNN4, KCNJ5) and GABA signalling (GABBR2, GABRD).

CONCLUSION

USP8 mutations occur in functioning and silent corticotrophinomas. They have pleiotropic effect, not limited to EGFR signalling, and affect expression levels of many genes involved in different pathways. Expression of GABA-related genes GABBR2, GNAL, GABARD and KCNJ5 correspond to functional status of the tumours.

The Role of Aberrant DNA Methylation in Misregulation of Gene Expression in Gonadotroph Nonfunctioning Pituitary Tumors

Gonadotroph nonfunctioning pituitary adenomas (NFPAs) are common intracranial tumors, but the role of aberrant epigenetic regulation in their development remains poorly understood. In this study, we investigated the effect of impaired CpG methylation in NFPAs. We determined DNA methylation and transcriptomic profiles in 32 NFPAs and normal pituitary sections using methylation arrays and sequencing, respectively. Ten percent of differentially methylated CpGs were correlated with gene expression, and the affected genes are involved in a variety of tumorigenesis-related pathways. Different proportions of gene body and promoter region localization were observed in CpGs with negative and positive correlations between methylation and gene expression, and different proportions of CpGs were located in 'open sea' and 'shelf/shore' regions. The expression of ~8% of genes differentially expressed in NFPAs was related to aberrant methylation. Methylation levels of seven CpGs located in the regulatory regions of FAM163A, HIF3A and PRSS8 were determined by pyrosequencing, and gene expression was measured by qRT-PCR and immunohistochemistry in 83 independent NFPAs. The results clearly confirmed the negative correlation between methylation and gene expression for these genes. By identifying which aberrantly methylated CpGs affect gene expression in gonadotrophinomas, our data confirm the role of aberrant methylation in pathogenesis of gonadotroph NFPAs.

DNA methylation profiling in nonfunctioning pituitary adenomas

Nonfunctioning pituitary adenomas (NFPAs) are among the most frequent intracranial tumors but their molecular background, including changes in epigenetic regulation, remains poorly understood. We performed genome-wide DNA methylation profiling of 34 NFPAs and normal pituitary samples. Methylation status of the selected genomic regions and expression level of corresponding genes were assessed in a group of 75 patients. NFPAs exhibited distinct global methylation profile as compared to normal pituitary. Aberrant DNA methylation appears to contribute to deregulation of the cancer-related pathways as shown by preliminary functional analysis. Promoter hypermethylation and decreased expression level of SFN, STAT5A, DUSP1, PTPRE and FGFR2 was confirmed in the enlarged group of NFPAs. Difference in the methylation profiles between invasive and non-invasive NFPAs is very slight. Nevertheless, invasiveness-related aberrant epigenetic deregulation of the particular genes was found including upregulation of ITPKB and downregulation CNKSR1 in invasive tumors.

Telomere length and TERT abnormalities in pituitary adenomas

OBJECTIVES

Pituitary adenomas (PAs) are among the most frequent intracranial tumors in humans. Abnormal telomerase activity and telomere lengthening are features of tumor cells. They may result from mutations in TERT promoter region, gene amplification or aberrant DNA methylation pattern. Such changes were found in variety of tumors including those of brain. Aim of the study was to evaluate the incidence of TERT abnormalities and to assess their role in telomere lengthening in PAs.

METHODS

Study involved 101 patients with PA including both nonfunctioning and functioning subtypes. Telomerase length as well as TERT mRNA level and gene amplification were estimated using quantitative PCR (qPCR). Promoter mutations were assessed using Sanger sequencing. The results from genome-wide DNA methylation profiling with HumanMethylation 450K (Illumina) were used for the analysis of TERT locus.

RESULTS

Variable telomere length was observed in patients, however no relationship with clinicopathological features was found. We observed a missense variant in TERT promoter in one patient only whereas increased TERT copy number were identified in 6 patients (5.6%). However no relationship between these results and telomere length or TERT expression was found. DNA methylation at TERT locus was not found to be changed when adenoma samples and normal tissue sections were compared.

CONCLUSION

The results indicate that telomerase abnormalities do not play a role in pathogenesis of pituitary tumors.

Downregulation of PTPRH (Sap-1) in colorectal tumors

Tyrosine phosphorylation is one of the basic mechanisms for signal transduction in the cell. Receptors exhibiting tyrosine kinase activity are widely involved in carcinogenesis and are negatively regulated by receptor protein tyrosine phosphatases (RPTP). Genes encoding different RPTPs are affected by aberrant epigenetic regulation in cancer. PTPRH (SAP-1) has been previously described to be overexpressed in colorectal cancer (CRC) and classified as an oncogenic factor. Previous microarray-based mRNA expression comparison of colorectal adenomas (AD), CRC and normal mucosa samples (NM) demonstrated that PTPRH tumor expression is the most reduced of all RPTP genes. qRT-PCR validation revealed gene downregulation for CRC (7.6-fold-change; P<0.0001) and AD (3.4-fold-change; P<0.0001) compared to NM. This was confirmed by immunohistochemical staining of tumor and NM sections as pronounced decrease of protein expression was observed in CRCs compared to the corresponding normal tissue. DNA methylation of two PTPRH promoter fragments was analyzed by pyrosequencing in a group of CRC, and AD patients as well as NM samples and CRC cell lines. The mean DNA methylation levels of these two regions were significantly higher in CRC than in NM. Both regions were highly methylated in SW480 and HCT116 cell lines contrary to unmethylated HT29 and COLO205. Cell lines with highly methylated promoters notably showed lower PTPRH expression levels, lower RNA II polymerase concentrations and higher levels of H3K27 trimethylation in the promoter and gene body, measured by chromatin immunoprecipitation. Cells were cultured with 5-aza-deoxycitidine and an increase in PTPRH expression was observed in SW480 and HCT116, whereas this was unchanged in the unmethylated cell lines. The results indicate that PTPRH is downregulated in colorectal tumors and its expression is epigenetically regulated via DNA methylation and chromatin modifications.

Aberrant DNA methylation of alternative promoter of DLC1 isoform 1 in meningiomas

DLC1 encodes GTPase-activating protein with a well-documented tumor suppressor activity. This gene is downregulated in various tumors through aberrant promoter hypermethylation. Five different DLC1 isoforms can be transcribed from alternative promoters. Tumor-related DNA methylation of the DLC1 isoform 1 alternative promoter was identified as being hypermethylated in meningiomas in genome-wide DNA methylation profiling. We determined the methylation pattern of this region in 50 meningioma FFPE samples and sections of 6 normal meninges, with targeted bisulfite sequencing. All histopathological subtypes of meningiomas showed similar and significant increase of DNA methylation levels. High DNA methylation was associated with lack of DLC1 protein expression in meningiomas as determined by immunohistochemistry. mRNA expression levels of 5 isoforms of DLC1 transcript were measured in an additional series of meningiomas and normal meninges. The DLC1 isoform 1 was found as the most expressed in normal control tissue and was significantly downregulated in meningiomas. Transfection of KT21 meningioma cell line with shRNA targeting DLC1 isoform 1 resulted in increased activation of RHO-GTPases assessed with pull-down assay, enhanced cell migration observed in scratch assay as well as slight increase of cell metabolism determind by MTT test. Results indicate that isoform 1 represents the main pool of DLC1 protein in meninges and its downregulation in meningiomas is associated with hypermethylation of CpG dinucleotides within the corresponding promoter region. This isoform is functional GAP protein and tumor suppressor and targeting of its expression results in the increase of DLC1 related cell processes: RHO activation and cell migration.

Expression changes of cell-cell adhesion-related genes in colorectal tumors

Epithelial tissues achieve a highly organized structure due to cell-cell junction complexes. Carcinogenesis is accompanied by changes in cell interactions and tissue morphology, which appear in the early stages of benign tumors and progress along with invasive potential. The aim of the present study was to analyze the changes in expression levels of genes encoding intercellular junction proteins that have been previously identified to be differentially expressed in colorectal tumors compared with normal mucosa samples (fold change, >2.5) in genome-wide expression profiling. The expression of 20 selected genes was assessed using quantitative reverse transcription polymerase chain reaction in 26 colorectal cancer, 42 adenoma and 24 normal mucosa samples. Between these tissue types, differences were observed in the mRNA levels of genes encoding adherens junction proteins (upregulation of CDH3 and CDH11, and downregulation of CDH19 and PTPRF), tight junction proteins (upregulation of CLDN1 and CLDN2, and downregulation of CLDN5, CLDN8, CLDN23, CLDN15, JAM2 and CGN) and desmosomes (upregulation of DSC3 and DSG3, and downregulation of DSC2), in addition to a decrease in the expression of certain other genes involved in intercellular connections: PCDHB14, PCDH7, MUPCDH and NEO1. The differences between tissue types were statistically significant, and separate clustering of normal adenoma and carcinoma samples was observed in a hierarchical clustering analysis. These results indicate that the morphological changes in neoplastic colon tissue that occur during the 'adenoma-carcinoma sequence' are accompanied by specific changes in the expression of multiple genes encoding the majority of cell-cell junction complexes. The particular differential expression patterns appear to be consistent among patients with cancer and adenoma, in addition to normal mucosa samples.

Promoter methylation and expression levels of selected hematopoietic genes in pediatric B-cell acute lymphoblastic leukemia

Background

Precursor B-cell acute lymphoblastic leukemia (B-cell ALL) is the most common neoplasm in children and is characterized by genetic and epigenetic aberrations in hematopoietic transcription factor (TF) genes. This study evaluated promoter DNA methylation and aberrant expression levels of early- and late-acting hematopoietic TF genes homeobox A4 and A5 (HOXA4 and HOXA5), Meis homeobox 1 (MEIS1), T-cell acute lymphocytic leukemia 1 (TAL1), and interferon regulatory factors 4 and 8 (IRF4 and IRF8) in pediatric B-cell ALL.

Methods

Blood samples of 38 ALL patients and 20 controls were obtained. DNA was treated with sodium bisulfite and DNA methylation level of HOXA4, HOXA5, MEIS1, TAL1, IRF4, and IRF8 was assessed using quantitative methylation-specific polymerase chain reaction (PCR). Relative gene expression was measured using quantitative reverse transcription-PCR.

Results

Aberrant methylation of TAL1, IRF8, MEIS1, and IRF4 was observed in 26.3%, 7.9%, 5.3%, and 2.6% patients, respectively, but not in controls. HOXA4 and HOXA5 were methylated in some controls and hypermethylated in 16% and 5% patients, respectively. IRF8, MEIS1, and TAL1 expression was lower in patients than in controls. MEIS1 expression was inversely correlated with white blood cell (WBC) count. HOXA4 expression was down-regulated in patients with high risk according to the National Cancer Institute (NCI) classification. TAL1 methylation was slightly elevated in patients aged >9 years and in patients showing relapse, suggesting its potential prognostic value.

Conclusion

Aberrant methylation and expression of the selected hematopoietic genes were correlated with demographic/clinical prognostic factors of pediatric ALL, such as age, WBC count, and NCI risk classification.

Regulation of the expression of claudin 23 by the enhancer of zeste 2 polycomb group protein in colorectal cancer

Altered epigenetic mechanisms, similar to gene mutations, contribute to the pathogenesis and molecular heterogeneity of neoplasms, including colorectal cancer (CRC). Enhancer of zeste 2 (EZH2) is a histone methyltransferase, which is involved in epigenetic gene silencing and is aberrantly expressed in CRC. Therefore, the identification of the genes regulated by EZH2 in CRC is important to improve current understanding of its role in cancer epigenetics. The present study used chromatin immunoprecipitation (ChIP) followed by deep sequencing to assess genome-wide EZH2‑DNA interactions in healthy or CRC mucosa samples. In total, 86.9/61.6 and 92.5/62.6 million tags were sequenced/mapped in healthy and CRC mucosa samples, respectively. The EZH2-binding densities were correlated with transcriptomic datasets and this demonstrated that the claudin-23 (CLDN23) gene, which encodes a component of cell-cell adhesion structures, was occupied by EZH2 and significantly silenced in CRC tissue. The measurement of DNA methylation at the CLDN23 promoter using pyrosequencing excluded the possibility that silencing of this gene in CRC patient samples was a result of DNA hypermethylation. Following treatment of the Colo205 and HT-29 CRC cell lines, with the EZH2 inhibitor, GSK126, the level of histone H3 lysine 27 trimethylation (H3K27me3) was reduced and the mRNA and protein expression levels of CLDN23 were increased. ChIP analysis confirmed that the level of H3K27m3 along the CLDN23 gene was decreased in the GSK126-treated cell lines. Furthermore, ChIP analysis of these samples detected histone H3 lysine 4 trimethylation (H3K4me3) at the CLDN23 promoter, demonstrating that the balance between H3K27me3 and H3K4me3 may underlie the regulation of the expression of CLDN23. The present study demonstrated an epigenetic link between the activity of the EZH2 methyltransferase at the CLDN23 locus and the expression of CLDN23 in CRC tissue.

Promoter DNA methylation and expression levels of HOXA4, HOXA5 and MEIS1 in acute myeloid leukemia

HOXA genes encode transcription factors, which are crucial for embryogenesis and tissue differentiation and are involved in the early stages of hematopoiesis. Aberrations in HOXA genes and their cofactor MEIS1 are found in human neoplasms, including acute myeloid leukemia (AML). The present study investigated the role of HOXA4, HOXA5 and MEIS1 promoter DNA methylation and mRNA expression in AML. Samples from 78 AML patients and 12 normal bone marrow (BM) samples were included. The levels of promoter DNA methylation were determined using quantitative methylation‑specific polymerase chain reaction (PCR; qMSP) and the relative expression levels were measured using reverse transcription quantitative PCR in Ficoll‑separated BM mononuclear cells and in fluorescent activated cell sorting‑sorted populations of normal hematopoietic progenitors. In total, 38.1 and 28.9% of the patients exhibited high methylation levels of HOXA4 and HOXA5, respectively, compared with the control samples, and MEIS1 methylation was almost absent. An inverse correlation between HOXA4 methylation and expression was identified in a group of patients with a normal karyotype (NK AML). An association between the genes was observed and correlation between the DNA methylation and expression levels of the HOXA gene promoter with the expression of MEIS1 was observed. Patients with favorable chromosomal aberrations revealed a low level of HOXA4 methylation and decreased expression levels of HOXA5 and MEIS1 compared with the NK AML and the adverse cytogenetic risk patients. The NK AML patients with NPM1 mutations exhibited elevated HOXA4 methylation and expression levels of HOXA5 and MEIS1 compared with the NPM1 wild‑type patients. Comparison of the undifferentiated BM‑derived hematopoietic CD34+CD38low, CD34+CD38+ and CD15+ cells revealed a gradual decrease in the expression levels of these three genes and an increase in HOXA4 promoter methylation. This differentiation‑associated variability was not observed in AML, which was classified according to the French‑American‑British system.

Microsatellite instability analysis in pituitary adenomas

OBJECTIVE

Mutator phenotypes with microsatellite instability (MSI) are observed in a subset of solid tumors including those localized in the brain. MSI arises from impaired DNA mismatch repair. It can be a potential marker of resistance to radiation and chemotherapy, as demonstrated for several cancer types. Our study aims are to investigate MSI incidence in pituitary adenomas (PA) with a currently recommended methodology.

METHODS

DNA was obtained from 107 patients with PA of which 83 adenomas were nonfunctioning, 13 somatotrophic, 9 lactotrophic and 2 corticotrophic. These were examined for MSI status by PCR and capillary electrophoresis using five quasimonomorphic microsatellite markers: BAT25, BAT26, NR21, NR24 and NR27; in accordance to current Bethesda guidelines.

RESULTS AND CONCLUSION

No microsatellite instability was detected in the tumor samples thus implying the lack of any clinical usefulness of MSI testing in PA cases.

Histone H3 lysine 27 acetylation is altered in colon cancer

Background

Histone post-translational modifications (PTMs) play an important role in the regulation of the expression of genes, including those involved in cancer development and progression. However, our knowledge of PTM patterns in human tumours is limited.

Methods

MS-based analyses were used to quantify global alterations of histone PTMs in colorectal cancer (CRC) samples. Histones isolated from 12 CRCs and their corresponding normal mucosa by acidic extraction were separated by SDS-PAGE and analysed by liquid chromatography-mass spectrometry.

Results

Among 96 modified peptides, 41 distinct PTM sites were identified, of which 7, 13, 11, and 10 were located within the H2A, H2B, H3, and H4 sequences, respectively, and distributed among the amino-terminal tails and the globular domain of the four histones. Modification intensities were quantified for 33 sites, of which 4 showed significant (p-value ≤ 0.05) differences between CRC tissues and healthy mucosa samples. We identified histone H3 lysine 27 acetylation (H3K27Ac) as a modification upregulated in CRC, which had not been shown previously.

Conclusions

The present results indicate the usefulness of a bottom-up proteomic approach for the detection of histone modifications at a global scale. The differential abundance of H3K27Ac mark in CRC, a PTM associated with active enhancers, suggests its role in regulating genes whose expression changes in CRC.

Repetitive genomic elements and overall DNA methylation changes in acute myeloid and childhood B-cell lymphoblastic leukemia patients

Aberrant epigenetic regulation is a hallmark of neoplastic cells. Increased DNA methylation of individual genes' promoter regions and decreases in overall DNA methylation level are both generally observed in cancer. In solid tumors, this global DNA hypomethylation is related to reduced methylation of repeated DNA elements (REs) and contributes to genome instability. The aim of the present study was to assess methylation level of LINE-1 and ALU REs and total 5-methylcytosine (5metC) content in adult acute myeloid leukemia (AML) (n = 58), childhood B-cell acute lymphoblastic leukemia (ALL) (n = 32), as the most frequent acute leukemias in two age categories and in normal adult bone marrow and children's blood samples. DNA pyrosequencing and ELISA assays were used, respectively. Global DNA hypomethylation was not observed in leukemia patients. Results revealed higher DNA methylation of LINE-1 in AML and ALL samples compared to corresponding normal controls. Elevated methylation of ALU and overall 5metC level were also observed in B-cell ALL patients. Differences of REs and global DNA methylation between AML cytogenetic-risk groups were observed, with the lowest methylation levels in intermediate-risk/cytogenetically normal patients. B-cell ALL is characterized by the highest DNA methylation level compared to AML and controls and overall DNA methylation is correlated with leukocyte count.

EGFR, PIK3CA, KRAS and BRAF mutations in meningiomas

Meningiomas are among the most frequent intracranial tumors. Treatment involves surgical resection with optional subsequent radiotherapy for high-grade meningiomas or radiosurgery following incomplete tumor removal. At present, no pharmacological agents are used as treatment. The use of targeted therapies has been considered, and specific therapies, including anti-EGFR treatment, have been clinically tested. The experience from the treatment of various types of cancers shows that patient outcome depends on the mutational status of particular molecules, including epithelial growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α (PIK3CA). Therefore, the aim of the present study was to assess the occurrence and potential use of these markers in patients with meningioma. In total, 55 formalin-fixed, paraffin-embedded meningioma samples were subjected to genomic sequencing of EGFR (exons 18–21), KRAS (exon 1), BRAF (exon 15) and PI3K (exons 9, 20). No mutations were identified in EGFR, KRAS or BRAF. Point mutations in PIK3CA were revealed in the samples of two patients with atypical and anaplastic meningiomas. Although these mutations appear to be rare, this result, along with previously reported findings, indicates that the PI3K/protein kinase B pathway may serve as a more reasonable molecular target for meningioma than EGFR.

TET2 Promoter DNA Methylation and Expression Analysis in Pediatric B-cell Acute Lymphoblastic Leukemia

TET2 is a novel tumor suppressor gene involved in several hematological malignancies of myeloid and lymphoid origin. Besides loss-of-function mutations and deletions, hypermethylation of the CpG island at the TET2 promoter was found in human cancer. Previous analysis revealed no TET2 mutations in acute lymphoblastic leukemia (ALL). Since the TET2 promoter methylation status in pediatric ALL has not been reported, the aim of the present study was to determine if promoter hypermethylation may be a mechanism of TET2 inactivation in a group of pediatric ALL cases. Methylation of TET2 promoter region in one (1/45) ALL B-common patient was detected by methylation specific polymerase chain reaction (PCR) and subsequently analyzed by bisulfite sequencing. We found no correlation between promoter methylation and gene expression, measured by quantitative reverse transcriptase-PCR, however the level of TET2 expression in ALL group was significantly decreased compared to children’s normal peripheral blood mononuclear cells and isolated B-cells. TET2 promoter hypermethylation seems to have limited clinical relevance in childhood B-cell ALL due to its low frequency.

Intracranial aneurysms in autosomal dominant polycystic kidney disease

BACKGROUND AND PURPOSE

ADPKD correlates with an increased frequency of ICANs, but universal screening for ICANs in patients with ADPKD is not currently recommended. The aim of our study was to determine which groups might benefit from screening by determining the prevalence of ICANs in the Polish ADPKD population and identifying any subgroups with an increased risk for ICANs.

MATERIALS AND METHODS

Eighty-three adult, predialysis-phase patients with ADPKD underwent screening for ICANs with MRA of the brain.

RESULTS

The prevalence of ICANs in the studied population was 16.9%, with 6% of the screened group requiring neurosurgical intervention. We also found that the frequency of ICANs increases with age, reaching 22.4% in patients older than 45 years. All diagnosed ICANs were small (< 9 mm) and were localized in the anterior circulation. In addition, MR imaging revealed arachnoid cysts in 4.8% of patients with ADPKD.

CONCLUSIONS

We suggest that patients older than 45 years with ADPKD be considered as candidates for screening for ICANs, and we propose a clinical algorithm for this subgroup. However, we could not find risk factors for ICANs in younger patients with ADPKD.

The promoter methylation and expression of the O6-methylguanine-DNA methyltransferase gene in uterine sarcoma and carcinosarcoma

O6-methylguanine-DNA methyltransferase (MGMT) gene promoter hypermethylation is observed in a number of solid tumors and is correlated with the silencing of MGMT expression. In glioblastoma patients treated with the alkylating agent temozolomide, MGMT gene methylation status was shown to have predictive value in terms of prolonged overall survival. Recently, temozolomide has demonstrated promising activity in the treatment of soft tissue sarcomas, including those of the uterus. The tissue specimens involving tumor samples and normal uterine fragments were obtained from nine patients with smooth muscle uterine sarcoma, 11 with stromal uterine sarcoma and 17 with mixed uterine tumors. MGMT gene promoter methylation was analyzed by combined bisulfite restriction analysis (COBRA) while its expression levels were assessed using the real-time reverse transcription polymerase chain reaction (qRT-PCR). MGMT promoter methylation was observed in 27% of all tumor samples analyzed. When stratified by the disease type, 55.5% (5/9) of smooth muscle sarcomas, 23.5% (4/17) of mixed uterine tumor tissues and 9% (1/11) of stromal sarcomas showed MGMT methylation. The MGMT promoter methylation was associated with lower levels of gene expression in tumors when compared with those with an unmethylated promoter (P=0.0232) or normal tissues (P=0.0141). To conclude, MGMT promoter methylation and downregulation of gene expression is observed in a fraction of carcinosarcomas and non-epithelial malignant tumors of corpus uteri. The assessment of MGMT promoter methylation status may potentially identify patients who would benefit from temozolomide treatment.

Estimation of groin recurrence risk in patients with squamous cell vulvar carcinoma by the assessment of marker gene expression in the lymph nodes

Background

Regional lymph node (LN) status is a well-known prognostic factor for vulvar carcinoma (VC) patients. Although the reliable LN assessment in VC is crucial, it presents significant diagnostic problems. We aimed to identify specific mRNA markers of VC dissemination in the LN and to address the feasibility of predicting the risk of nodal recurrence by the patterns of gene expression.

Methods

Sentinel and inguinal LN samples from 20 patients who had undergone surgery for stage T_1-3, N_0-2, M₀ primary vulvar squamous cell carcinoma were analyzed. Gene expression profiles were assessed in four metastatic [LN(+)] and four histologically negative [LN(−)] lymph node samples obtained from four VC patients, by the Affymetrix U133 Plus 2.0 gene expression microarrays. Of the set of genes of the highest expression in the metastatic LNs compared to LN(−), seven candidate marker genes were selected: PERP, S100A8, FABP5, SFN, CA12, JUP and CSTA, and the expression levels of these genes were further analyzed by the real-time reverse transcription polymerase chain reaction (qRT-PCR) in 71 LN samples.

Results

All of the seven genes in question were significantly increased in LN(+) compared to LN(−) samples. In the initial validation of the seven putative markers of metastatic LN, the Cox proportional hazard model pointed to SFN, CA12 and JUP expression to significantly relate to the time to groin recurrence in VC patients.

Conclusions

Our findings first provided evidence that SFN, CA12 and JUP have a potential of marker genes for the prediction of the groin recurrence LN in VC patients.

Methyl-CpG binding column-based identification of nine genes hypermethylated in colorectal cancer

DNA methylation is an epigenetic event that plays a role in gene expression regulation. Alterations in DNA methylation contribute to cancer development and progression. The aim of this study was to identify gene promoters aberrantly methylated in colorectal tumor tissue in comparison to normal colonic mucosa. Analyses were performed on two pooled DNA samples: from normal and cancerous tissue obtained from CRC patients. DNA was fractionated according to methylation degree with the use of affinity column containing methyl-CpG binding domain. To identify novel hypermethylated gene promoters, methylated DNA from normal and from cancerous tissues were analyzed with the use of promoter microarrays. We identified nine novel genes hypermethylated in colorectal cancer. The frequency of their promoter methylation was assessed in the larger group of patients (n = 77): KCNK12 (methylated in 41% of CRC patients), GPR101 (40%), CDH2 (45%), BARX1 (56%), CNTFR (22%), SYT6 (64%), SMO (21%), EPHA5 (43%), and GSPT2 (21%). The results of gene expression level analysis suggest the role of promoter methylation in downregulation of six out of nine genes examined. We did not find correlation between gene methylation and age, gender, tumor grade or stage. Importantly, in stage IV CRC methylation of GPR101 correlated with longer time to progression (P = 0.0042; HR = 2.5468; 95% CI 1.5391-10.0708).

Does adjuvant fluoropyrimidine-based chemotherapy provide a benefit for patients with resected rectal cancer who have already received neoadjuvant radiochemotherapy? A systematic review of randomised trials

BACKGROUND

The results of the recently published large European randomised study in rectal cancer (European Organisation for Research and Treatment of Cancer 22921 trial) do not support current guidelines recommending postoperative chemotherapy for patients who have previously undergone preoperative radiochemotherapy or radiotherapy [radio(chemo)therapy]. To evaluate this discrepancy further, a systematic review of relevant randomised trials was undertaken.

MATERIALS AND METHODS

A systematic literature search was carried out in order to identify randomised studies exploring adjuvant chemotherapy against observation in patients with rectal cancer previously treated with preoperative radio(chemo)therapy.

RESULTS

A statistically significant benefit of adjuvant chemotherapy was not found in any of the four relevant randomised trials. Non-protocolised subgroup analysis of one study indicated a beneficial effect of adjuvant chemotherapy for high rectal tumours and for patients downstaged to ypT0-2N0 but no effect for low-lying rectal tumours. However, the body of evidence indicates that patients downstaged after radio(chemo)therapy to ypT0-2N0 disease are not candidates for testing adjuvant chemotherapy in future trials due to the considerable over-treatment anticipated by this manoeuvre.

CONCLUSIONS

To resolve the issue in question, a meta-analysis of relevant studies is required, and new trials should be launched to explore new drug combinations against observation. Currently, delivery of adjuvant chemotherapy in patients undergoing preoperative radio(chemo)therapy is not evidence based.

CHFR gene is neither mutated nor hypermethylated in ovarian cancer

BACKGROUND

CHFR is a mitotic checkpoint protein that under mitotic stress (caused also by taxanes) delays progression into mitosis.

METHODS

We looked for CHFR gene (605,209) alterations and its promoter hypermethylation in 48 ovarian carcinomas either sensitive or resistant to taxane treatment. We used single-strand conformation polymorphism analysis, sequencing and methylation-specific polymerase chain reaction.

RESULTS

Neither mutations in the CHFR gene nor hypermethylation of its promoter region were found. A novel single nucleotide polymorphism (Val154Val) was identified in exon 5 of alternatively spliced transcript.

CONCLUSIONS

Our results indicate that CHFR gene status cannot serve as a molecular predictor of ovarian cancer sensitivity to taxanes.

[Antenatal homeostasis of insulin and glucose in the fetus with cytomegalovirus infection]

Factors of effect on the fetal glucose level can be of maternal, placental or fetal origin. The level of fetal insulin during gestation is regulated by the potentials of the endogenous fetal production on one hand and on the other by the factors (primarily glucaemia) that stimulate or inhibit its production. The aim of this paper was to analyze in which way and to what extent the congenital infection with the Cytomegalovirus disturbs the metabolism of the fetal glucose and insulin. Umbilical venous cord blood was obtained by cordocentesis at 22 to 29 weeks gestation from 52 women referred to our clinic for fetal karyotyping and scatological analysis of fetal CMV infection. To determine the effect of Cytomegalovirus (CMV) infection on insulin and glucose fetal homeostatis, we performed cordocentesis in 18 patients (group A) with proved congenital CMV fetal infection. Control group (B) consisted of 34 patients in whom blood samples were taken for fetal karyotyping. Maternal and fetal glucose levels were 3.95 mmol/l and 3.15 mmol/l in group A and 4.00 and 3.62 mmol/l in group B, respectively. Maternal average insulin level in group A was 14.45 mU/ml and in fetuses 10.64 mU/ml, while in group B maternal and fetal insulin levels were 12.85 mU/ml and 15.35 mU/ml, respectively. Maternal/fetal (M/F) insulin ratio was in group A 1.35, and in group B 0.84. Statistical analysis showed significantly lower glucose and insulin levels and also higher maternal/fetal insulin ratio in fetuses affected by CMV infection (t = 1.4, p < 0.001). Consequences of congenital CMV infection were fetal hypoglucaemia and hypoinsulinemia.

[Metabolism of amino acids in fetuses with cytomegalovirus infection and growth retardation]

Aim of the study was to evaluate correlation between valine and glycine, representatives of essential and nonessential amino acids, in fetuses appropriate and small for gestational age with congenital cytomegalovirus infection. Umbilical venous cord blood was obtained by cordocentesis at 22 to 29 weeks' gestation from 18 women (11 in appropriate for gestational age--A, and seven in small for gestational age--B) fetuses with CMV infection. Plasma amino acids were measured with an Beckman M 121 amino acid analyzer. Maternal valine level was 136.0 mmol/l; fetal valine in AGA and SGA fetuses: 219 and 189 mmol/l respectively. Fetomaternal valine ratio was significantly lower in SGA group (1.39 mmol/l-SGA, 1.61 mmol/l AGA, t = -6.9, p < 0.001). Glycine level in maternal blood was 139.0 mmol/l; fetal in SGA and AGA fetuses 137 mmol/l and 176 mmol/l, respectively. Fetomaternal glycine ratio was also significantly lower in SGA group than in AGA, 1.01 and 1.27 respectively (t = -2.96, p < 0.001). Valine/Glycine maternal and fetal ratio did not show any difference between groups. In congenitally CMV infected fetuses with intrauterine growth retardation there is a decreased valine and glycine level, compared to the congenitally CMV infected fetuses with normal intrauterine growth. There is a lower fetal concentration of these amino acids compared to the maternal level in SGA fetuses. A decreased glycine level compared to the valine level has also been found in congenitally CMV infected fetuses with intrauterine growth retardation.

[Bacterial vaginosis. Epidemiology and risk factors]

Bacterial vaginosis (BV) is a change in vaginal ecosystem where lactobacilli dominate, flora is absent or greatly reduced, and replaced with a mixed, predominantly anaerobic flora, consisting of Gardnerella vaginalis, Mycoplasma hominis, Mobiluncus spp, Bacteroides spp, Prevotela spp, Peptostreptococcus spp, Fusobacterium spp and Porphyromonas spp. The concentration of bacteria increases from 100 to 1000 fold in women with BV compared to healthy women. BV has been formerly known as nonspecific vaginitis, Haemophilus vaginitis, Corynebacterium vaginitis, Gardnerella vaginitis and anaerobic vaginintis. BV is the most prevalent form of vaginal disturbances in reproductive age women. The average incidence of BV varies: 10-35% in patients visiting gynaecological wards, 10-30% in patients visiting obstetric wards and 20-60% in patients visiting services of sexually transmitted diseases. A typical clinical symptom of BV is malodorous vaginal discharge. However, more than 50% of all women with BV are asymptomatic. BV has been associated with many gynaecological and obstetric complications such as cervicitis, salpingitis, endometritis, postoperative infections, urinary tract infections, pelvic inflammatory disease, mild abnormal Pap smear results and possible link with cervical intraepithelial neoplasia, preterm delivery, premature rupture of the membranes, chorioamnionitis and postpartum endometritis. Factors that increase the risk of BV are multiple partners, exposure to semen, prior trichomoniasis, intrauterine device usage, smoking, indigent population and frequent use of scented soap. Diagnosis of BV is established by Amsel's criteria of which three of four are the following: presence of homogeneous discharge, vaginal fluid pH > 4.5, positive amine test and microscopic analysis of Gram stained smear of vaginal discharge where "clue" cells (epithelial vaginal cells covered with mass of adherent bacteria, mostly coccobacilli) should be detected. The treatment of patients with BV consist of metronidazole or clindamycin, per os or intravaginally. The treatment of asymptomatic women and male sex partners of women with BV is controversial. The aim of the study was to establish the occurrence rate of BV in our women and potential factors increasing the risk of BV. We examined 166 women at the Institute of Microbiology and Immunology, University School of Medicine, Belgrade. Diagnosis of BV was established by Amsel's criteria. Each woman filled in a special questionnaire. Pregnant women were excluded. BV was diagnosed in 25% (33/166) of women. BV was more common among women with multiple partners. The most prevalent clinical symptom of BV was malodorous vaginal discharge. Vaginal symptoms became more evident after intercourse. Taking into consideration the occurrence rate of BV and its connection with numerous gynaecological and obstetric sequelae, and taking into account that the diagnosis of BV is quick, simple and inexpensive, we suggest that the examination of BV in women becomes a usual procedure.

[Importance of disposable medical materials and instruments in the prevention of intrahospital infections]

Possibility for transmission of infectious diseases from patients to medical staff or vice versa is significant. Protective measures for patients as well as physicians must be applied and controlled. The aim was to investigate the microbiological status of disposable and reusable instruments and materials in order to establish the difference between them in protection from microorganisms. From the 122 samples of wet swab from reusables, 70.5% were bacteriologically negative and 29.5% positive. Seventy percent of isolated bacteria were a pathogens, and 30% were pathogens. All 80 samples of wet swab from disposable products were sterile. The frequency of bacteriologically negative samples among disposable products is highly significant (p < 0.01). These results confirm that the level of protection is higher if disposable products are used. Reusables should be replaced by disposable materials to decrease the incidence of nosocomial infections.

How congenital cytomegalovirus infection changes insulin and glucose homeostasis in affected fetuses

Factors affecting the fetal glucose level can be of maternal, placental or fetal origin. The level of fetal insulin during gestation is regulated by the potential of the endogenous fetal production on one hand, and on the other, by the factors (primarily glycaemia) that stimulate or inhibit its production. The aim of this paper was to analyze in which way and to what extent congenital infection with the cytomegalovirus disturbs the metabolism of fetal glucose and insulin. Umbilical venous cord blood was obtained by cordocentesis at 22 to 29 weeks gestation from 52 women referred to our clinic for fetal karyotyping and scatological analysis of fetal CMV infection. To determine the effect of cytomegalovirus (CMV) infection on insulin and glucose fetal homeostasis, cordocentesis was performed in 18 patients (group A) with proven congenital CMV fetal infection. The control group (B) consisted of 34 patients in whom blood samples were taken for fetal karyotyping. Maternal and fetal glucose levels were 3.95 mmol/l and 3.15 mmol/l in group A and 4.00 and 3.62 mmol/l in group B, respectively. Maternal average insulin level in group A was 14.45 mU/ml and in fetuses 10.64 mU/ml, while group B maternal and fetal insulin levels were 12.38 mU/ml and 15.35 mU/ml, respectively. Maternal/fetal (M/F) insulin ratio was 1.35 in group A and in group B, 0.84. Statistical analysis showed significantly lower glucose and insulin levels and also a higher maternal/fetal insulin ratio in fetuses affected by CMV infection (t = 1.4 p < 0.001). Consequences of congenital CMV infection were fetal hypoglycaemia and hypoinsulinemia.

Essential and nonessential amino acids in appropriate and small for gestational age fetuses with congenital cytomegalovirus infection

The aim of the study was to evaluate the correlation between valine and glycine, representatives of essential and nonessential amino acids, in appropriate and small fetuses for gestational age with congenital cytomegalovirus (CMV) infection. Umbilical venous cord blood was obtained by cordocentesis at 22 to 29 weeks' gestation from 18 women (11 in appropriate for gestational age (AGA) -A, and 7 in small for gestational age (SGA) -B) fetuses with CMV infection. Plasma amino acids were measured with a Beckman M 121 amino acid analyzer. Maternal valine level was 136.0 mmol/l; fetal valine in AGA and SGA fetuses: 219 and 189 mmol/l, respectively. Fetomaternal valine ratio was significantly lower in the SGA group (1.39 mmol/l-SGA, 1.61 mmol/l AGA, t = 6.9 p < 0.001). The glycine level in maternal blood was 139.0 mmol/l; fetal in SGA and AGA fetuses 137 mmol/l, and 176 mmol/l, respectively. The fetomaternal glycine ratio was also significantly lower in the SGA group than in AGA. 1.01 and 1.27, respectively (t = -2.96, p < 0.001). Valine/glycine maternal and fetal ratio did not show any difference between groups. In the congenital CMV infected fetuses with intrauterine growth retardation there were decreased valine and glycine levels compared to the congenitally CMV infected fetuses with normal intrauterine growth. There was a lower fetal concentration of these amino acids compared to the maternal level in SGA fetuses. A decreased glycine level compared to the valine level has also been found in congenitally CMV infected fetuses with intrauterine growth retardation.

[T lymphocytes, non-malignant and premalignant changes in the planocellular epithelium of the uterine cervix]

T lymphocytes play an important role in the immune response to both neoplasia and viral infection. Normally, about 60% of T lymphocytes in the peripheral blood are T4 (helper) lymphocytes, while 20-30% are T8(suppressor) lymphocytes. When this ratio is inverted, most significant changes occur. The aim of the study was to examine the T4/T8 lymphocyte ratio in the peripheral blood of patients with nonmalignant and premalignant changes of the cervical epithelium and to compare it with that in patients without any cytological or colposcopical cervical abnormality. The results show a significant decrease of the T4/T8 lymphocyte ratio in the peripheral blood of patients with leukokeratosis (1.55) and especially of those with cervical intraepithelial neoplasia (1.19), compared with the results of the control group (2.31). These findings, as well as the knowledge of the importance of immune response in the control of the onset of malignancy, that the determination of T4/T8 lymphocyte ratio might be helpful in the prediction of the degree of premalignant cervical chance and indicate patient's follow-up.