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Olli Kallioniemi

Publications and source records attributed to Olli Kallioniemi.

17 recordsLinked to original sources
PubMed2007

ProteomeBinders: planning a European resource of affinity reagents for analysis of the human proteome.

ProteomeBinders is a new European consortium aiming to establish a comprehensive resource of well-characterized affinity reagents, including but not limited to antibodies, for analysis of the human proteome. Given the huge diversity of the proteome, the scale of the project is potentially immense but nevertheless feasible in the context of a pan-European or even worldwide coordination.

Affinity Labels↗
PubMed2006

TMPRSS2 fusions with oncogenic ETS factors in prostate cancer involve unbalanced genomic rearrangements and are associated with HDAC1 and epigenetic reprogramming.

Translocations fusing the strong androgen-responsive gene, TMPRSS2, with ERG or other oncogenic ETS factors may facilitate prostate cancer development. Here, we studied 18 advanced prostate cancers for ETS factor alterations, using reverse transcription-PCR and DNA and RNA array technologies, and identified putative ERG downstream gene targets from the microarray data of 410 prostate samples. Out of the 27 ETS factors, ERG was most frequently overexpressed. Seven cases showed TMPRSS2:ERG gene fusions, whereas the TMPRSS2:ETV4 fusion was seen in one case. In five out of six tumors with high ERG expression, array-CGH analysis revealed interstitial 2.8 Mb deletions between the TMPRSS2 and ERG loci, or smaller, unbalanced rearrangements. In silico analysis of the ERG gene coexpression patterns revealed an association with high expression of the histone deacetylase 1 gene, and low expression of its target genes. Furthermore, we observed increased expression of WNT-associated pathways and down-regulation of tumor necrosis factor and cell death pathways. In summary, our data indicate that the TMPRSS2:ERG translocation is common in advanced prostate cancer and occurs by virtue of unbalanced genomic rearrangements. Activation of ERG by fusion with TMPRSS2 may lead to epigenetic reprogramming, WNT signaling, and down-regulation of cell death pathways, implicating ERG in several hallmarks of cancer with potential therapeutic importance.

Cell Line, Tumor↗
PubMed2006

Human Protein Atlas charts a diverse terrain.

A complete set of high-quality antibodies against the human proteome would constitute a remarkable resource for the analysis of protein abundances in tissues, facilitating systematic protein expression profiling in health and disease. In two recent papers, Swedish researchers describe a concerted effort towards producing a 'Human Protein Atlas' by combining high-throughput antibody generation with immunohistochemical profiling of tissue microarrays.

Database Management Systems↗
PubMed2006

Profiling genetic variation along the androgen biosynthesis and metabolism pathways implicates several single nucleotide polymorphisms and their combinations as prostate cancer risk factors.

Several candidate genes along androgen pathway have been suggested to affect prostate cancer risk but no single gene seems to be overwhelmingly important for a large fraction of the patients. In this study, we first screened for variants in candidate genes and then chose to explore the association between 18 variants and prostate cancer risk by genotyping DNA samples from unselected (n = 847) and familial (n = 121) prostate cancer patients and population controls (n = 923). We identified a novel single nucleotide polymorphism (SNP) in the CYP19A1 gene, T201M, with a mild significant association with prostate cancer [odds ratio (OR), 2.04; 95% confidence interval (95% CI), 1.03-4.03; P = 0.04]. Stratified analysis revealed that this risk was most apparent in patients with organ-confined (T(1)-T(2)) and low-grade (WHO grade 1) tumors (OR, 5.42; 95% CI, 2.33-12.6; P < 0.0001). In contrast, CYP17A1 -34T>C alteration was associated with moderate to poorly differentiated (WHO grade 2-3) organ-confined disease (OR, 1.42; 95% CI, 1.09-1.83; P = 0.007). We also tested a multigenic model of prostate cancer risk by calculating the joint effect of CYP19A1 T201M with five other common SNPs. Individuals carrying both the CYP19A1 and KLK3 -252A>G variant alleles had a significantly increased risk for prostate cancer (OR, 2.87; 95% CI, 1.10-7.49; P = 0.03). In conclusion, our results suggest that several SNPs along the androgen pathway, especially in CYP19A1 and CYP17A1, may influence prostate cancer development and progression. These genes may have different contributions to distinct clinical subsets as well as combinatorial effects in others illustrating that profiling and joint analysis of several genes along each pathway may be needed to understand genetic contributions to prostate cancer etiology.

Aged↗
PubMed2006

Integrated breast cancer genomics.

Predicting survival and therapy responses of breast cancer patients is a significant challenge. Two studies in this issue of Cancer Cell present a novel integrated analysis of genomic and transcriptomic profiles of 145 primary breast cancers and 51 established cell lines. Data from clinical tumors highlighted mechanisms of disease and facilitated identification of potential therapeutic targets and prognostic biomarkers. An extensive well-characterized cancer cell line resource opens up opportunities to explore the determinants of cellular responses to existing and emerging therapies. Taken together, these studies illustrate how integrated molecular profiling may one day significantly impact diagnosis and therapeutic choice in human breast cancer.

Breast Neoplasms↗
PubMed2006

Novel genomic aberrations in testicular germ cell tumors by array-CGH, and associated gene expression changes.

INTRODUCTION: Testicular germ cell tumors of adolescent and young adult men (TGCTs) generally have near triploid and complex karyotypes. The actual genes driving the tumorigenesis remain essentially to be identified. MATERIALS AND METHODS: To determine the detailed DNA copy number changes, and investigate their impact on gene expression levels, we performed an integrated microarray profiling of TGCT genomes and transcriptomes. We analyzed 17 TGCTs, three precursor lesions, and the embryonal carcinoma cell lines, NTERA2 and 2102Ep, by comparative genomic hybridization microarrays (array-CGH), and integrated the data with transcriptome profiles of the same samples. RESULTS: The gain of chromosome arm 12p was, as expected, the most common aberration, and we found CCND2, CD9, GAPD, GDF3, NANOG, and TEAD4 to be the therein most highly over-expressed genes. Additional frequent genomic aberrations revealed some shorter chromosomal segments, which are novel to TGCT, as well as known aberrations for which we here refined boundaries. These include gains from 7p15.2 and 21q22.2, and losses of 4p16.3 and 22q13.3. Integration of DNA copy number information to gene expression profiles identified that BRCC3, FOS, MLLT11, NES, and RAC1 may act as novel oncogenes in TGCT. Similarly, DDX26, ERCC5, FZD4, NME4, OPTN, and RB1 were both lost and under-expressed genes, and are thus putative TGCT suppressor genes. CONCLUSION: This first genome-wide integrated array-CGH and gene expression profiling of TGCT provides novel insights into the genome biology underlying testicular tumorigenesis.

Adolescent↗
PubMed2005

Differentiation of human embryonal carcinomas in vitro and in vivo reveals expression profiles relevant to normal development.

Embryonal carcinoma is a histologic subgroup of testicular germ cell tumors (TGCTs), and its cells may follow differentiation lineages in a manner similar to early embryogenesis. To acquire new knowledge about the transcriptional programs operating in this tumor development model, we used 22k oligo DNA microarrays to analyze normal and neoplastic tissue samples from human testis. Additionally, retinoic acid-induced in vitro differentiation was studied in relevant cell lines. We identified genes characterizing each of the known histologic subtypes, adding up to a total set of 687 differentially expressed genes. Among these, there was a significant overrepresentation of gene categories, such as genomic imprinting and gene transcripts associated to embryonic stem cells. Selection for genes highly expressed in the undifferentiated embryonal carcinomas resulted in the identification of 58 genes, including pluripotency markers, such as the homeobox genes NANOG and POU5F1 (OCT3/4), as well as GAL, DPPA4, and NALP7. Interestingly, abundant expression of several of the pluripotency genes was also detected in precursor lesions and seminomas. By use of tissue microarrays containing 510 clinical testicular samples, GAL and POU5F1 were up-regulated in TGCT also at the protein level and hence validated as diagnostic markers for undifferentiated tumor cells. The present study shows the unique gene expression profiles of each histologic subtype of TGCT from which we have identified deregulated components in selected processes operating in normal development, such as WNT signaling and DNA methylation.

Carcinoma in Situ↗
PubMed2005

NMD microarray analysis for rapid genome-wide screen of mutated genes in cancer.

Gene mutations play a critical role in cancer development and progression, and their identification offers possibilities for accurate diagnostics and therapeutic targeting. Finding genes undergoing mutations is challenging and slow, even in the post-genomic era. A new approach was recently developed by Noensie and Dietz to prioritize and focus the search, making use of nonsense-mediated mRNA decay (NMD) inhibition and microarray analysis (NMD microarrays) in the identification of transcripts containing nonsense mutations. We combined NMD microarrays with array-based CGH (comparative genomic hybridization) in order to identify inactivation of tumor suppressor genes in cancer. Such a "mutatomics" screening of prostate cancer cell lines led to the identification of inactivating mutations in the EPHB2 gene. Up to 8% of metastatic uncultured prostate cancers also showed mutations of this gene whose loss of function may confer loss of tissue architecture. NMD microarray analysis could turn out to be a powerful research method to identify novel mutated genes in cancer cell lines, providing targets that could then be further investigated for their clinical relevance and therapeutic potential.

Animals↗
PubMed2003

A novel strategy for microarray quality control using Bayesian networks.

MOTIVATION: High-throughput microarray technologies enable measurements of the expression levels of thousands of genes in parallel. However, microarray printing, hybridization and washing may create substantial variability in the quality of the data. As erroneous measurements may have a drastic impact on the results by disturbing the normalization schemes and by introducing expression patterns that lead to incorrect conclusions, it is crucial to discard low quality observations in the early phases of a microarray experiment. A typical microarray experiment consists of tens of thousands of spots on a microarray, making manual extraction of poor quality spots impossible. Thus, there is a need for a reliable and general microarray spot quality control strategy. RESULTS: We suggest a novel strategy for spot quality control by using Bayesian networks, which contain many appealing properties in the spot quality control context. We illustrate how a non-linear least squares based Gaussian fitting procedure can be used in order to extract features for a spot on a microarray. The features we used in this study are: spot intensity, size of the spot, roundness of the spot, alignment error, background intensity, background noise, and bleeding. We conclude that Bayesian networks are a reliable and useful model for microarray spot quality assessment. SUPPLEMENTARY INFORMATION: http://sigwww.cs.tut.fi/TICSP/SpotQuality/.

Algorithms↗
PubMed2003

RNAi microarray analysis in cultured mammalian cells.

RNA interference (RNAi) mediated by small interfering RNAs (siRNAs) is a powerful new tool for analyzing gene knockdown phenotypes in living mammalian cells. To facilitate large-scale, high-throughput functional genomics studies using RNAi, we have developed a microarray-based technology for highly parallel analysis. Specifically, siRNAs in a transfection matrix were first arrayed on glass slides, overlaid with a monolayer of adherent cells, incubated to allow reverse transfection, and assessed for the effects of gene silencing by digital image analysis at a single cell level. Validation experiments with HeLa cells stably expressing GFP showed spatially confined, sequence-specific, time- and dose-dependent inhibition of green fluorescence for those cells growing directly on microspots containing siRNA targeting the GFP sequence. Microarray-based siRNA transfections analyzed with a custom-made quantitative image analysis system produced results that were identical to those from traditional well-based transfection, quantified by flow cytometry. Finally, to integrate experimental details, image analysis, data display, and data archiving, we developed a prototype information management system for high-throughput cell-based analyses. In summary, this RNAi microarray platform, together with ongoing efforts to develop large-scale human siRNA libraries, should facilitate genomic-scale cell-based analyses of gene function.

Cell Line, Tumor↗
PubMed2002

High frequency of BRAF mutations in nevi.

To evaluate the timing of mutations in BRAF (v-raf murine sarcoma viral oncogene homolog B1) during melanocytic neoplasia, we carried out mutation analysis on microdissected melanoma and nevi samples. We observed mutations resulting in the V599E amino-acid substitution in 41 of 60 (68%) melanoma metastases, 4 of 5 (80%) primary melanomas and, unexpectedly, in 63 of 77 (82%) nevi. These data suggest that mutational activation of the RAS/RAF/MAPK pathway in nevi is a critical step in the initiation of melanocytic neoplasia but alone is insufficient for melanoma tumorigenesis.

Cell Transformation, Neoplastic↗
PubMed2002

Expression of cytokeratins 17 and 5 identifies a group of breast carcinomas with poor clinical outcome.

While several prognostic factors have been identified in breast carcinoma, the clinical outcome remains hard to predict for individual patients. Better predictive markers are needed to help guide difficult treatment decisions. In a previous study of 78 breast carcinoma specimens, we noted an association between poor clinical outcome and the expression of cytokeratin 17 and/or cytokeratin 5 mRNAs. Here we describe the results of immunohistochemistry studies using monoclonal antibodies against these markers to analyze more than 600 paraffin-embedded breast tumors in tissue microarrays. We found that expression of cytokeratin 17 and/or cytokeratin 5/6 in tumor cells was associated with a poor clinical outcome. Moreover, multivariate analysis showed that in node-negative breast carcinoma, expression of these cytokeratins was a prognostic factor independent of tumor size and tumor grade.

Animals↗
PubMed2002

Morphological spot counting from stacked images for automated analysis of gene copy numbers by fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) is a molecular diagnostic technique in which a fluorescent labeled probe hybridizes to a target nucleotide sequence of deoxyribose nucleic acid. Upon excitation, each chromosome containing the target sequence produces a fluorescent signal (spot). Because fluorescent spot counting is tedious and often subjective, automated digital algorithms to count spots are desirable. New technology provides a stack of images on multiple focal planes throughout a tissue sample. Multiple-focal-plane imaging helps overcome the biases and imprecision inherent in single-focal-plane methods. This paper proposes an algorithm for global spot counting in stacked three-dimensional slice FISH images without the necessity of nuclei segmentation. It is designed to work in complex backgrounds, when there are agglomerated nuclei, and in the presence of illumination gradients. It is based on the morphological top-hat transform, which locates intensity spikes on irregular backgrounds. After finding signals in the slice images, the algorithm groups these together to form three-dimensional spots. Filters are employed to separate legitimate spots from fluorescent noise. The algorithm is set in a comprehensive toolbox that provides visualization and analytic facilities. It includes simulation software that allows examination of algorithm performance for various image and algorithm parameter settings, including signal size, signal density, and the number of slices.

Algorithms↗