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- Georgiadis, Panagiotis, et al.
(author)
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Evolving DNA methylation and gene expression markers of B-cell chronic lymphocytic leukemia are present in pre-diagnostic blood samples more than 10 years prior to diagnosis
- 2017
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In: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 18
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Journal article (peer-reviewed)abstract
- BACKGROUND: B-cell chronic lymphocytic leukemia (CLL) is a common type of adult leukemia. It often follows an indolent course and is preceded by monoclonal B-cell lymphocytosis, an asymptomatic condition, however it is not known what causes subjects with this condition to progress to CLL. Hence the discovery of prediagnostic markers has the potential to improve the identification of subjects likely to develop CLL and may also provide insights into the pathogenesis of the disease of potential clinical relevance.RESULTS: We employed peripheral blood buffy coats of 347 apparently healthy subjects, of whom 28 were diagnosed with CLL 2.0-15.7 years after enrollment, to derive for the first time genome-wide DNA methylation, as well as gene and miRNA expression, profiles associated with the risk of future disease. After adjustment for white blood cell composition, we identified 722 differentially methylated CpG sites and 15 differentially expressed genes (Bonferroni-corrected p < 0.05) as well as 2 miRNAs (FDR < 0.05) which were associated with the risk of future CLL. The majority of these signals have also been observed in clinical CLL, suggesting the presence in prediagnostic blood of CLL-like cells. Future CLL cases who, at enrollment, had a relatively low B-cell fraction (<10%), and were therefore less likely to have been suffering from undiagnosed CLL or a precursor condition, showed profiles involving smaller numbers of the same differential signals with intensities, after adjusting for B-cell content, generally smaller than those observed in the full set of cases. A similar picture was obtained when the differential profiles of cases with time-to-diagnosis above the overall median period of 7.4 years were compared with those with shorted time-to-disease. Differentially methylated genes of major functional significance include numerous genes that encode for transcription factors, especially members of the homeobox family, while differentially expressed genes include, among others, multiple genes related to WNT signaling as well as the miRNAs miR-150-5p and miR-155-5p.CONCLUSIONS: Our findings demonstrate the presence in prediagnostic blood of future CLL patients, more than 10 years before diagnosis, of CLL-like cells which evolve as preclinical disease progresses, and point to early molecular alterations with a pathogenetic potential.
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| 2. |
- Krauskopf, Julian, et al.
(author)
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MicroRNA profile for health risk assessment : environmental exposure to persistent organic pollutants strongly affects the human blood microRNA machinery
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Journal article (peer-reviewed)abstract
- Persistent organic pollutants (POPs) are synthetic chemical substances that accumulate in our environment. POPs such as polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane (DDT) have been classified as carcinogenic to humans and animals. Due to their resistance to biodegradation humans are still exposed to these compounds worldwide. We aim to evaluate the miRNA and transcriptomic response of a human population exposed to POPs. The miRNA and transcriptomic response was measured in blood of healthy subjects by microarray technology and associated with the serum concentrations of six PCB congeners, DDE (a common DDT metabolite), and HCB. A total of 93 miRNA levels appeared significantly associated with the POP-exposure (FDR < 0.05). The miRNA profile includes four tumor suppressor miRNAs, namely miR-193a-3p, miR-152, miR-31-5p and miR-34a-5p. Integration of the miRNA profile with the transcriptome profile suggests an interaction with oncogenes such as MYC, CCND1, BCL2 and VEGFA. We have shown that exposure to POPs is associated with human miRNA and transcriptomic responses. The identified miRNAs and target genes are related to various types of cancer and involved in relevant signaling pathways like wnt and p53. Therefore, these miRNAs may have great potential to contribute to biomarker-based environmental health risk assessment.
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| 3. |
- Nieters, Alexandra, et al.
(author)
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Prediagnostic immunoglobulin E levels and risk of chronic lymphocytic leukemia, other lymphomas and multiple myeloma-results of the European Prospective Investigation into Cancer and Nutrition.
- 2014
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In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 35:12, s. 2716-2722
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Journal article (peer-reviewed)abstract
- Previous epidemiological studies suggest an inverse association between allergies, marked by elevated immunoglobulin (Ig) E levels, and non-Hodgkin lymphoma (NHL) risk. The evidence, however, is inconsistent and prospective data are sparse. We examined the association between prediagnostic total (low: <20; intermediate: 20-100; high >100 kU/l) and specific IgE (negative: <0.35; positive ≥0.35 kU/I) concentrations against inhalant antigens and lymphoma risk in a study nested within the European Prospective Investigation into Cancer and Nutrition cohort. A total of 1021 incident cases and matched controls of NHL, multiple myeloma (MM) and Hodgkin lymphoma with a mean follow-up time of 7 years were investigated. Multivariate-adjusted odds ratios (ORs) with 95% confidence intervals (CI) were calculated by conditional logistic regression. Specific IgE was not associated with the risk of MM, B-cell NHL and B-cell NHL subtypes. In contrast, total IgE levels were inversely associated with the risk of MM [high level: OR = 0.40 (95% CI = 0.21-0.79)] and B-cell NHL [intermediate level: OR = 0.68 (95% CI = 0.53-0.88); high level: OR = 0.62 (95% CI = 0.44-0.86)], largely on the basis of a strong inverse association with chronic lymphocytic leukemia [CLL; intermediate level: OR = 0.49 (95% CI = 0.30-0.80); high level: OR = 0.13 (95% CI = 0.05-0.35)] risk. The inverse relationship for CLL remained significant for those diagnosed 5 years after baseline. The findings of this large prospective study demonstrated significantly lower prediagnostic total IgE levels among CLL and MM cases compared with matched controls. This corresponds to the clinical immunodeficiency state often observed in CLL patients prior to diagnosis. No support for an inverse association between prediagnostic levels of specific IgE and NHL risk was found.
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| 4. |
- Wibom, Carl, et al.
(author)
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Glioma Gwas Hits - Markers for Risk or for Prognosis?
- 2014
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In: Neuro-Oncology. - : Oxford University Press. - 1522-8517 .- 1523-5866. ; 16:Suppl. 2, s. ii109-ii110
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Journal article (peer-reviewed)abstract
- One obstacle to developing new treatments for glioma is the generally poor understanding of glioma aetiology. The only generally accepted environmental risk factor or glioma is ionizing radiation. Glioma aetiology has also been shown to contain a genetic component, in part through observations that individuals in families with a history of glioma have an elevated risk of developing glioma themselves. The genetic component in glioma aetiology has been further substantiated through genome wide association studies (GWAS). These studies have identified associations between a number of common genetic variants and an increased glioma risk. However, the studies have all been of case-control design (i.e. including cases at diagnosis), and as such they presumably suffer from a degree of survival bias. Survival bias risks being introduced in a study when rapidly fatal cases are not included. This is an inherent risk of case-control designs, which is particularly pronounced when studying a disease with very poor prognosis, such as glioma. Ultimately, survival bias may result in erroneous conclusions, as it is impossible to separate associations with prognosis from associations with risk of disease. To accurately confirm previously identified glioma risk variants, and ascertain whether they are associated with risk or with prolonged survival, we investigated these variants in a set of pre-diagnostic serum samples (594 cases and 591 matched controls). Analyses of population based, pre-diagnostic samples eliminates the risk of survival bias, and enables distinction between genetic variants associated with glioma risk (i.e. aetiology) and genetic variants associated with prognosis. The serum samples were acquired through The Janus Serum Bank, a Norwegian population based biobank reserved for cancer research. Variant detection was achieved by means of cycling temperature capillary electrophoresis. Our investigation confirmed the association with glioma risk for the investigated variants within five genomic regions; 8q24.21 (CCDC26), 9p21.3 (CDKN2B-AS1), 11q23.3 (PHLDB1), 17p13.1 (TP53), and 20q13.33 (RTEL1). This is indicative of these variants being truly associated with glioma risk, and thus may impact gliomagenesis. However, previously identified risk variants within the 5p15.33 (TERT) and 7p11.2 (EGFR) could not be positively confirmed by this study. The lack of positive confirmation raises the question whether EGFR and TERT genetic variants are linked with prolonged survival, rather than with glioma aetiology.
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