Search

PurposeThe purpose of this study was to compare the clinical characteristics and the survival of CHEK2 mutation positive and CHEK2 mutation negative patients diagnosed with bladder or kidney cancer.Materials and methods1016 patients with bladder and 402 cases with kidney cancer and 8302 controls were genotyped for four CHEK2 variants: 1100delC, del5395, IVS2+1G>A and I157T. Predictors of survival were determined among CHEK2 pathogenic variant carriers using the Cox proportional hazards model. The median follow-up was 17.5 years. Covariates included age (≤60; >61 years), sex (female; male), clinical characteristics (stage: TNM, grade, histopathological type), smoking status (non-smoking; smoking) and cancer family history (negative; positive).ResultsWe found no impact of CHEK2 mutations on bladder or kidney cancer survival. However, we observed a possible increased survival in the subgroup of patients with stage T1 bladder cancer with CHEK2 mutations but this did not meet statistical significance (HR = 0.14; 95% CI 0.02-1.04; p = 0.055). Moreover, we observed that the missense mutations were more frequent in the low grade invasive bladder cancer patient group (OR = 7.9; 95% CI 1.50-42.1; p = 0.04) and in patients with bladder cancer with stage Ta (OR = 2.4; 95% CI 1.30-4.55; p = 0.006). The different results where missense mutations occurs less often we observed among patients with high grade invasive bladder cancer (OR = 0.12; 95% CI 0.02-0.66; p = 0.04) and those with stage T1 disease (OR = 0.2; 95% CI 0.07-0.76; p = 0.01). Our investigations revealed that any mutation in CHEK2 occurs more often among patients with stage Ta bladder cancer (OR = 2.0; 95% CI 1.19-3.47; p = 0.01) and less often in patients with stage T1 disease (OR = 0.31; 95% CI 0.12-0.78; p = 0.01). In the kidney cancer patients, truncating mutations were present more often in the group with clear cell carcinoma GII (OR = 8.0; 95% CI 0.95-67.7; p = 0.05). The 10-year survival for all CHEK2 mutation carriers with bladder cancer was 33% and for non-carriers 11% (p = 0.15). The 10-year survival for CHEK2 mutation carriers with kidney cancer 34% and for non-carriers 20% (p = 0.5).ConclusionCHEK2 mutations were not associated with any change in bladder or kidney cancer survival regardless of their age, sex, smoking status and family history. We observed a potentially protective effect of CHEK2 mutations on survival for patients with stage T1 bladder cancer. CHEK2 missense mutations were more common among patients with low grade invasive bladder cancer and in patients with stage Ta diease. The frequencies of the I157T CHEK2 pathogenic variant were less in patients with high grade invasive bladder cancer and those with stage T1 disease. Among patients with bladder cancer with stage Ta disease, the OR for any mutation in CHEK2 was 2.0 but for those with stage T1 disease, the OR was 0.3. We observed truncating CHEK2 mutations were associated with kidney cancer patients with GII clear cell carcinoma.

Epigenome-wide association studies seek to identify DNA methylation sites associated with clinical outcomes. Difference in observed methylation between specific cell-subtypes is often of interest; however, available samples often comprise a mixture of cells. To date, cell-subtype estimates have been obtained from mixed-cell DNA data using linear regression models, but the accuracy of such estimates has not been critically assessed. We evaluated linear regression performance for cell-subtype specific methylation estimation using a 450K methylation array dataset of both mixed-cell and cell-subtype sorted samples from six healthy males. CpGs associated with each cell-subtype were first identified using t-tests between groups of cell-subtype sorted samples. Subsequent reduced panels of reliably accurate CpGs were identified from mixed-cell samples using an accuracy heuristic (D). Performance was assessed by comparing cell-subtype specific estimates from mixed-cells with corresponding cell-sorted mean using the mean absolute error (MAE) and the Coefficient of Determination (R2). At the cell-subtype level, methylation levels at 3272 CpGs could be estimated to within a MAE of 5% of the expected value. The cell-subtypes with the highest accuracy were CD56+ NK (R2 = 0.56) and CD8+T (R2 = 0.48), where 23% of sites were accurately estimated. Hierarchical clustering and pathways enrichment analysis confirmed the biological relevance of the panels. Our results suggest that linear regression for cell-subtype specific methylation estimation is accurate only for some cell-subtypes at a small fraction of cell-associated sites but may be applicable to EWASs of disease traits with a blood-based pathology. Although sample size was a limitation in this study, we suggest that alternative statistical methods will provide the greatest performance improvements.

INTRODUCTION:Prostate cancer is one of the most commonly diagnosed malignancies among men in Western populations. Evidence reported in the literature suggests that zinc may be related to prostate cancer. In this study we evaluated the association of serum zinc levels and polymorphisms in genes encoding zinc-dependent proteins with prostate cancer in Poland. METHODS:The study group consisted of 197 men affected with prostate cancer and 197 healthy men. Serum zinc levels were measured and 5 single nucleotide polymorphisms in MMP-1, MMP-2, MMP-7, MMP-13, MT2A genes were genotyped. RESULTS:The mean serum zinc level was higher in prostate cancer patients than in healthy controls (898.9±12.01 μg/l vs. 856.6±13.05 μg/l, p853.0-973.9 μg/l). Among five analyzed genetic variants, rs11568818 in MMP-7 appeared to be correlated with 2-fold increased prostate cancer risk (OR = 2.39, 95% CI = 1.19-4.82, p = 0.015). CONCLUSION:Our results suggest a significant correlation of higher serum zinc levels with the diagnosis of prostate cancer. The polymorphism rs11568818 in MMP-7 gene was also associated with an increased prostate cancer risk in Poland.

The association of BRCA1/2 mutations with melanoma is not completely determined; the interpretation of variants of unknown significance is also problematic. To evaluate these issues we explored the molecular basis of melanoma risk by performing whole-exome sequencing on a cohort of 96 unrelated Polish early-onset melanoma patients and targeted sequencing of BRCA1/2 genes on additional 30 melanoma patients with familial aggregation of breast and other cancers. Sequencing was performed on peripheral blood. We evaluated MutationTaster, Polyphen2, SIFT, PROVEAN algorithms, analyzed segregation with cancer disease (in both families with identified BRCA2 variants) and in one family performed LOH (based on 2 primary tumors). We found neither pathogenic mutations nor variants of unknown significance within BRCA1. We identified two BRCA2 variants of unknown significance: c.9334G>A and c.4534 C>T. Disease allele frequency was evaluated by genotyping of 1230 consecutive melanoma cases, 5000 breast cancer patients, 3500 prostate cancers and 9900 controls. Both variants were found to be absent among unselected cancer patients and healthy controls. The MutationTaster, Polyphen2 and SIFT algorithms indicate that c.9334G>A is a damaging variant. Due to lack of tumour tissue LOH analysis could not be performed for this variant. The variant segregated with the disease. The c.4534 C>T variant did not segregate with disease, there was no LOH of the variant. The c.9334G>A variant, classified as a rare variant of unknown significance, on current evidence may predisposes to cancers of the breast, prostate and melanoma. Functional studies to describe how the DNA change affects the protein function and a large multi-center study to evaluate its penetrance are required.

DNA methylation is an epigenetic mark that is influenced by environmental factors and is associated with changes to gene expression and phenotypes. It may link environmental exposures to disease etiology or indicate important gene pathways involved in disease pathogenesis. We identified genomic regions that are differentially methylated in T cells of patients with relapsing remitting multiple sclerosis (MS) compared to healthy controls. DNA methylation was assessed at 450,000 genomic sites in CD4+ and CD8+ T cells purified from peripheral blood of 94 women with MS and 94 healthy women, and differentially methylated regions were identified using bumphunter. Differential DNA methylation was observed near four loci: MOG/ZFP57, HLA-DRB1, NINJ2/LOC100049716, and SLFN12. Increased methylation of the first exon of the SLFN12 gene was observed in both T cell subtypes and remained present after restricting analyses to samples from patients who had never been on treatment or had been off treatment for more than 2.5 years. Genes near the regions of differential methylation in T cells were assessed for differential expression in whole blood samples from a separate population of 1,329 women with MS and 97 healthy women. Gene expression of HLA-DRB1, NINJ2, and SLFN12 was observed to be decreased in whole blood in MS patients compared to controls. We conclude that T cells from MS patients display regions of differential DNA methylation compared to controls, and corresponding gene expression differences are observed in whole blood. Two of the genes that showed both methylation and expression differences, NINJ2 and SLFN12, have not previously been implicated in MS. SLFN12 is a particularly compelling target of further research, as this gene is known to be down-regulated during T cell activation and up-regulated by type I interferons (IFNs), which are used to treat MS.

An increasing number of genome-wide association (GWA) studies are now using the higher resolution 1000 Genomes Project reference panel (1000G) for imputation, with the expectation that 1000G imputation will lead to the discovery of additional associated loci when compared to HapMap imputation. In order to assess the improvement of 1000G over HapMap imputation in identifying associated loci, we compared the results of GWA studies of circulating fibrinogen based on the two reference panels. Using both HapMap and 1000G imputation we performed a meta-analysis of 22 studies comprising the same 91,953 individuals. We identified six additional signals using 1000G imputation, while 29 loci were associated using both HapMap and 1000G imputation. One locus identified using HapMap imputation was not significant using 1000G imputation. The genome-wide significance threshold of 5×10-8 is based on the number of independent statistical tests using HapMap imputation, and 1000G imputation may lead to further independent tests that should be corrected for. When using a stricter Bonferroni correction for the 1000G GWA study (P-value < 2.5×10-8), the number of loci significant only using HapMap imputation increased to 4 while the number of loci significant only using 1000G decreased to 5. In conclusion, 1000G imputation enabled the identification of 20% more loci than HapMap imputation, although the advantage of 1000G imputation became less clear when a stricter Bonferroni correction was used. More generally, our results provide insights that are applicable to the implementation of other dense reference panels that are under development.

Placental CRH production increases with advancing pregnancy in women and its course predicts gestational length. We hypothesized that CRH gene expression in the placenta is epigenetically controlled setting gestational trajectories characteristic of normal and pathological pregnancies. Here we determined histone modification and DNA methylation levels and DNA methylation patterns at the CRH promoter in primary trophoblast cultures by chromatin immunoprecipitation combined with clonal bisulfite sequencing and identified the transcriptionally active epialleles that associate with particular histone modifications and transcription factors during syncytialisation and cAMP-stimulation. CRH gene expression increased during syncytial differentiation and cAMP stimulation, which was associated with increased activating and decreased repressive histone modification levels at the promoter. DNA methylation levels remained unchanged. The nine CpGs of the CRH proximal promoter were partially and allele-independently methylated displaying many (>100) epialleles. RNA-polymerase-II (Pol-II) bound only to three particular epialleles in cAMP-stimulated cells, while phospho-cAMP response element-binding protein (pCREB) bound to only one epiallele, which was different from those selected by Pol-II. Binding of TATA-binding protein increased during syncytial differentiation preferentially at epialleles compatible with Pol-II and pCREB binding. Histone-3 acetylation was detected only at epialleles targeted by Pol-II and pCREB, while gene activating histone-4 acetylation and histone-3-lysine-4 trimethylation occurred at CRH epialleles not associated with Pol-II or pCREB. The suppressive histone-3-lysine-27 trimethyl and-lysine-9 trimethyl modifications showed little or no epiallele preference. The epiallele selectivity of activating histone modifications and transcription factor binding demonstrates the epigenetic and functional diversity of the CRH gene in trophoblasts, which is controlled predominantly by the patterns, not the overall extent, of promoter methylation. We propose that conditions impacting on epiallele distribution influence the number of transcriptionally active CRH gene copies in the trophoblast cell population determining the gestational trajectory of placental CRH production in normal and pathological pregnancies.

p53 is expressed as multiple smaller isoforms whose functions in cancer are not well understood. The p53 isoforms demonstrate abnormal expression in different cancers, suggesting they are important in modulating the function of full-length p53 (FLp53). The quantification of relative mRNA expression has routinely been performed using real-time PCR (qPCR). However, there are serious limitations when detecting p53 isoforms using this method, particularly for formalin-fixed paraffin-embedded (FFPE) tissues. The use of FFPE tumours would be advantageous to correlate expression of p53 isoforms with important clinical features of cancer. One alternative method of RNA detection is the hybridization-based QuantiGene 2.0 Assay, which has been shown to be advantageous for the detection of RNA from FFPE tissues. In this pilot study, we compared the QuantiGene 2.0 Assay to qPCR for the detection of FLp53 and its isoform Δ40p53 in matched fresh frozen (FF) and FFPE breast tumours. FLp53 mRNA expression was detected using qPCR in FF and FFPE tissues, but Δ40p53 mRNA was only detectable in FF tissues. Similar results were obtained for the QuantiGene 2.0 Assay. FLp53 relative mRNA expression was shown to be strongly correlated between the two methods (R2 = 0.9927, p = 0.0031) in FF tissues, however Δ40p53 was not (R2 = 0.4429, p = 0.3345). When comparing the different methods for the detection of FLp53 mRNA from FFPE and FF samples, no correlation (R2 = 0.0002, p = 0.9863) was shown using the QuantiGene 2.0 Assay, and in contrast, the level of expression was highly correlated between the two tissues using qPCR (R2 = 0.8753, p = 0.0644). These results suggest that both the QuantiGene 2.0 Assay and qPCR methods are inadequate for the quantification of Δ40p53 mRNA in FFPE tissues. Therefore, alternative methods of RNA detection and quantification are required to study the relative expression of Δ40p53 in FFPE samples.

Genome wide association studies (GWAS) have established association of ARID5B and IKZF1 variants with childhood acute lymphoblastic leukemia (ALL). Epidemiological studies suggest that environmental factors alone appear to make a relatively minor contribution to disease risk. The polygenic nature of childhood ALL predisposition together with the timing of environmental triggers may hold vital clues for disease etiology. This study presents results from an Australian GWAS of childhood ALL cases (n = 358) and population controls (n = 1192). Furthermore, we utilised family trio (n = 204) genotypes to extend our investigation to gene-environment interaction of significant loci with parental exposures before conception, and child's sex and age. Thirteen SNPs achieved genome wide significance in the population based case/control analysis; ten annotated to ARID5B and three to IKZF1. The most significant SNPs in these regions were ARID5B rs4245595 (OR 1.63, CI 1.38-1.93, P = 2.13×10(-9)), and IKZF1 rs1110701 (OR 1.69, CI 1.42-2.02, p = 7.26×10(-9)). There was evidence of gene-environment interaction for risk genotype at IKZF1, whereby an apparently stronger genetic effect was observed if the mother took folic acid or if the father did not smoke prior to pregnancy (respective interaction P-values: 0.04, 0.05). There were no interactions of risk genotypes with age or sex (P-values >0.2). Our results evidence that interaction of genetic variants and environmental exposures may further alter risk of childhood ALL however, investigation in a larger population is required. If interaction of folic acid supplementation and IKZF1 variants holds, it may be useful to quantify folate levels prior to initiating use of folic acid supplements.

Nucleotide excision repair (NER) orchestrates the repair of helix distorting DNA damage, induced by both ultraviolet radiation (UVR) and cisplatin. There is evidence that the global genome repair (GGR) arm of NER is dysfunctional in melanoma and it is known to have limited induction in melanoma cell lines after cisplatin treatment. The aims of this study were to examine mRNA transcript levels of regulators of GGR and to investigate the downstream effect on global transcript expression in melanoma cell lines after cisplatin treatment and in melanoma tumours. The GGR regulators, BRCA1 and PCNA, were induced in melanocytes after cisplatin, but not in melanoma cell lines. Transcripts associated with BRCA1, BRCA2, ATM and CHEK2 showed altered expression in melanoma cell lines after cisplatin treatment. In melanoma tumour tissue BRCA1 transcript expression correlated with poor survival and XPB expression correlated with solar elastosis levels. Taken together, these findings provide evidence of the mechanisms underlying NER deficiency in melanoma.

Genetic factors explain a majority of risk variance for age-related macular degeneration (AMD). While genome-wide association studies (GWAS) for late AMD implicate genes in complement, inflammatory and lipid pathways, the genetic architecture of early AMD has been relatively under studied. We conducted a GWAS meta-analysis of early AMD, including 4,089 individuals with prevalent signs of early AMD (soft drusen and/or retinal pigment epithelial changes) and 20,453 individuals without these signs. For various published late AMD risk loci, we also compared effect sizes between early and late AMD using an additional 484 individuals with prevalent late AMD. GWAS meta-analysis confirmed previously reported association of variants at the complement factor H (CFH) (peak P = 1.5×10(-31)) and age-related maculopathy susceptibility 2 (ARMS2) (P = 4.3×10(-24)) loci, and suggested Apolipoprotein E (ApoE) polymorphisms (rs2075650; P = 1.1×10(-6)) associated with early AMD. Other possible loci that did not reach GWAS significance included variants in the zinc finger protein gene GLI3 (rs2049622; P = 8.9×10(-6)) and upstream of GLI2 (rs6721654; P = 6.5×10(-6)), encoding retinal Sonic hedgehog signalling regulators, and in the tyrosinase (TYR) gene (rs621313; P = 3.5×10(-6)), involved in melanin biosynthesis. For a range of published, late AMD risk loci, estimated effect sizes were significantly lower for early than late AMD. This study confirms the involvement of multiple established AMD risk variants in early AMD, but suggests weaker genetic effects on the risk of early AMD relative to late AMD. Several biological processes were suggested to be potentially specific for early AMD, including pathways regulating RPE cell melanin content and signalling pathways potentially involved in retinal regeneration, generating hypotheses for further investigation.

In the last four years, Genome-Wide Association Studies (GWAS) have identified sixteen low-penetrance polymorphisms on fourteen different loci associated with colorectal cancer (CRC). Due to the low risks conferred by known common variants, most of the 35% broad-sense heritability estimated by twin studies remains unexplained. Recently our group performed a case-control study for eight Single Nucleotide Polymorphisms (SNPs) in 4 CRC genes. The present investigation is a follow-up of that study. We have genotyped six SNPs that showed a positive association and carried out a meta-analysis based on eight additional studies comprising in total more than 8000 cases and 6000 controls. The estimated recessive odds ratio for one of the SNPs, rs3219489 (MUTYH Q338H), decreased from 1.52 in the original Swedish study, to 1.18 in the Swedish replication, and to 1.08 in the initial meta-analysis. Since the corresponding summary probability value was 0.06, we decided to retrieve additional information for this polymorphism. The incorporation of six further studies resulted in around 13000 cases and 13000 controls. The newly updated OR was 1.03. The results from the present large, multicenter study illustrate the possibility of decreasing effect sizes with increasing samples sizes. Phenotypic heterogeneity, differential environmental exposures, and population specific linkage disequilibrium patterns may explain the observed difference of genetic effects between Sweden and the other investigated cohorts.

Narrow arterioles in the retina have been shown to predict hypertension as well as other vascular diseases, likely through an increase in the peripheral resistance of the microcirculatory flow. In this study, we performed a genome-wide association study in 18,722 unrelated individuals of European ancestry from the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium and the Blue Mountain Eye Study, to identify genetic determinants associated with variations in retinal arteriolar caliber. Retinal vascular calibers were measured on digitized retinal photographs using a standardized protocol. One variant (rs2194025 on chromosome 5q14 near the myocyte enhancer factor 2C MEF2C gene) was associated with retinal arteriolar caliber in the meta-analysis of the discovery cohorts at genome-wide significance of P-value

Activating mutations in the receptor tyrosine kinase FLT3 are one of the most frequent somatic mutations in acute myeloid leukemia (AML). Internal tandem duplications of the juxtamembrane region of FLT3 (FLT3/ITD) constitutively activate survival and proliferation pathways, and are associated with a poor prognosis in AML. We suspected that alteration of small non-coding microRNA (miRNA) expression in these leukemia cells is involved in the transformation process and used miRNA microarrays to determine the miRNA signature from total RNA harvested from FLT3/ITD expressing FDC-P1 cells (FD-FLT3/ITD). This revealed that a limited set of miRNAs appeared to be affected by expression of FLT3/ITD compared to the control group consisting of FDC-P1 parental cells transfected with an empty vector (FD-EV). Among differentially expressed miRNAs, we selected miR-16, miR-21 and miR-223 to validate the microarray data by quantitative real-time RT-PCR showing a high degree of correlation. We further analyzed miR-16 expression with FLT3 inhibitors in FLT3/ITD expressing cells. MiR-16 was found to be one of most significantly down-regulated miRNAs in FLT3/ITD expressing cells and was up-regulated upon FLT3 inhibition. The data suggests that miR-16 is acting as a tumour suppressor gene in FLT3/ITD-mediated leukemic transformation. Whilst miR-16 has been reported to target multiple mRNAs, computer models from public bioinformatic resources predicted a potential regulatory mechanism between miR-16 and Pim-1 mRNA. In support of this interaction, miR-16 was shown to suppress Pim-1 reporter gene expression. Further, our data demonstrated that over-expression of miR-16 mimics suppressed Pim-1 expression in FD-FLT3/ITD cells suggesting that increased miR-16 expression contributes to depletion of Pim-1 after FLT3 inhibition and that miR-16 repression may be associated with up-regulated Pim-1 in FLT3/ITD expressing cells.

While hybridization based analysis of the cortical transcriptome has provided important insight into the neuropathology of schizophrenia, it represents a restricted view of disease-associated gene activity based on predetermined probes. By contrast, sequencing technology can provide un-biased analysis of transcription at nucleotide resolution. Here we use this approach to investigate schizophrenia-associated cortical gene expression.The data was generated from 76 bp reads of RNA-Seq, aligned to the reference genome and assembled into transcripts for quantification of exons, splice variants and alternative promoters in postmortem superior temporal gyrus (STG/BA22) from 9 male subjects with schizophrenia and 9 matched non-psychiatric controls. Differentially expressed genes were then subjected to further sequence and functional group analysis. The output, amounting to more than 38 Gb of sequence, revealed significant alteration of gene expression including many previously shown to be associated with schizophrenia. Gene ontology enrichment analysis followed by functional map construction identified three functional clusters highly relevant to schizophrenia including neurotransmission related functions, synaptic vesicle trafficking, and neural development. Significantly, more than 2000 genes displayed schizophrenia-associated alternative promoter usage and more than 1000 genes showed differential splicing (FDR

UnlabelledEpigenetic regulation of genes involves the coordination of DNA methylation and histone modifications to maintain transcriptional status. These two features are frequently disrupted in malignancy such that critical genes succumb to inactivation. 5-aza-2'-deoxycytidine (5-aza-dC) is an agent which inhibits DNA methyltransferase, and holds great potential as a treatment for cancer, yet the extent of its effectiveness varies greatly between tumour types. Previous evidence suggests expression status after 5-aza-dC exposure cannot be explained by the DNA methylation status alone.AimWe sought to identify chromatin changes involved with short and long term gene reactivation following 5-aza-dC exposure. Two colorectal cancer cell lines, HCT116 and SW480, were treated with 5-aza-dC and then grown in drug-free media to allow DNA re-methylation. DNA methylation and chromatin modifications were assessed with bisulfite sequencing and Chromatin Immuno-Precipitation analysis.ResultsIncreased H3 acetylation, H3K4 tri-methylation and loss of H3K27 tri-methylation were associated with reactivation. Hypermethylated genes that did not show increased acetylation were transiently expressed with 5-aza-dC treatment before reverting to an inactive state. Three reactivated genes, CDO1, HSPC105 and MAGEA3, were still expressed 10 days post 5-aza-dC treatment and displayed localised hypomethylation at the transcriptional start site, and also an increased enrichment of histone H3 acetylation.ConclusionsThese observations suggest that hypomethylation alone is insufficient to reactivate silenced genes and that increased Histone H3 acetylation in unison with localised hypomethylation allows long term reversion of these epigenetically silenced genes. This study suggests that combined DNA methyltransferase and histone deacetylase inhibitors may aid long term reactivation of silenced genes.

Genetic factors associated with the risk of smoking related cancers have until recently remained elusive. Since the publication of a genome-wide association study (GWAS) on lung cancer new genetic loci have been identified that appear to be associated with disease risk. In this replication study we genotyped 14 single nucleotide polymorphisms (SNPs) located at the 5p12.3-p15.33, 6p21.3-p22.1, 6q23-q27 and 15q25.1 loci in 874 lung, 450 bladder, 418 laryngeal cancer cases and cancer-free controls, matched by year of birth and sex to the cases. Our results revealed that loci in the chromosome region 15q25.1 (rs16969968[A], rs8034191[G]) and 5p15 (rs402710[T]) are associated with lung cancer risk in the Polish population (smoking status adjusted OR = 1.45, 1.35, 0.77; p ≤ 0.0001, 0.0005, 0.002; 95%CI 1.23-1.72, 1.14-1.59, 0.66-0.91 respectively). None of the other regions analyzed herein were implicated in the risk of lung, bladder or laryngeal cancer. This study supports previous findings on lung cancer but fails to show association of SNPs located in 15q25.1 and 5p15 region with other smoking related cancers like bladder and laryngeal cancer.

BackgroundSeveral lines of evidence suggest that transcription factors are involved in the pathogenesis of Multiple Sclerosis (MS) but complete mapping of the whole network has been elusive. One of the reasons is that there are several clinical subtypes of MS and transcription factors that may be involved in one subtype may not be in others. We investigate the possibility that this network could be mapped using microarray technologies and contemporary bioinformatics methods on a dataset derived from whole blood in 99 untreated MS patients (36 Relapse Remitting MS, 43 Primary Progressive MS, and 20 Secondary Progressive MS) and 45 age-matched healthy controls.Methodology/principal findingsWe have used two different analytical methodologies: a non-standard differential expression analysis and a differential co-expression analysis, which have converged on a significant number of regulatory motifs that are statistically overrepresented in genes that are either differentially expressed (or differentially co-expressed) in cases and controls (e.g., V$KROX_Q6, p-value Conclusions/significanceOur analysis uncovered a network of transcription factors that potentially dysregulate several genes in MS or one or more of its disease subtypes. The most significant transcription factor motifs were for the Early Growth Response EGR/KROX family, ATF2, YY1 (Yin and Yang 1), E2F-1/DP-1 and E2F-4/DP-2 heterodimers, SOX5, and CREB and ATF families. These transcription factors are involved in early T-lymphocyte specification and commitment as well as in oligodendrocyte dedifferentiation and development, both pathways that have significant biological plausibility in MS causation.

It is well established that Multiple Sclerosis (MS) is an immune mediated disease. Little is known about what drives the differential control of the immune system in MS patients compared to unaffected individuals. MicroRNAs (miRNAs) are small non-coding nucleic acids that are involved in the control of gene expression. Their potential role in T cell activation and neurodegenerative disease has recently been recognised and they are therefore excellent candidates for further studies in MS. We investigated the transcriptome of currently known miRNAs using miRNA microarray analysis in peripheral blood samples of 59 treatment naïve MS patients and 37 controls. Of these 59, 18 had a primary progressive, 17 a secondary progressive and 24 a relapsing remitting disease course. In all MS subtypes miR-17 and miR-20a were significantly under-expressed in MS, confirmed by RT-PCR. We demonstrate that these miRNAs modulate T cell activation genes in a knock-in and knock-down T cell model. The same T cell activation genes are also up-regulated in MS whole blood mRNA, suggesting these miRNAs or their analogues may provide useful targets for new therapeutic approaches.