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| 2. |
- Andersson-Evelönn, Emma, 1983-, et al.
(författare)
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Combining epigenetic and clinicopathological variables improves specificity in prognostic prediction in clear cell renal cell carcinoma
- 2020
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Ingår i: Journal of Translational Medicine. - : Springer Science and Business Media LLC. - 1479-5876. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Metastasized clear cell renal cell carcinoma (ccRCC) is associated with a poor prognosis. Almost one-third of patients with non-metastatic tumors at diagnosis will later progress with metastatic disease. These patients need to be identified already at diagnosis, to undertake closer follow up and/or adjuvant treatment. Today, clinicopathological variables are used to risk classify patients, but molecular biomarkers are needed to improve risk classification to identify the high-risk patients which will benefit most from modern adjuvant therapies. Interestingly, DNA methylation profiling has emerged as a promising prognostic biomarker in ccRCC. This study aimed to derive a model for prediction of tumor progression after nephrectomy in non-metastatic ccRCC by combining DNA methylation profiling with clinicopathological variables.Methods: A novel cluster analysis approach (Directed Cluster Analysis) was used to identify molecular biomarkers from genome-wide methylation array data. These novel DNA methylation biomarkers, together with previously identified CpG-site biomarkers and clinicopathological variables, were used to derive predictive classifiers for tumor progression.Results: The “triple classifier” which included both novel and previously identified DNA methylation biomarkers together with clinicopathological variables predicted tumor progression more accurately than the currently used Mayo scoring system, by increasing the specificity from 50% in Mayo to 64% in our triple classifier at 85% fixed sensitivity. The cumulative incidence of progress (pCIP5yr) was 7.5% in low-risk vs 44.7% in high-risk in M0 patients classified by the triple classifier at diagnosis.Conclusions: The triple classifier panel that combines clinicopathological variables with genome-wide methylation data has the potential to improve specificity in prognosis prediction for patients with non-metastatic ccRCC.
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| 3. |
- Bayisa, Fekadu L., et al.
(författare)
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Computed Tomography Image Estimation by Statistical Learning Methods
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- There is increasing interest in computed tomography (CT) image estimations from magnetic resonance (MR) images. The estimated CT images canbe utilised for attenuation correction, patient positioning, and dose planningin diagnostic and radiotherapy workflows. This study presents a statisticallearning method for CT image estimation. We have used predefined tissuetype information in a Gaussian mixture model to explore the estimation.The performance of our method was evaluated using cross-validation on realdata. In comparison with the existing model-based CT image estimationmethods, the proposed method has improved the estimation, particularly inbone tissues. Evaluation of our method shows that it is a promising methodto generate CT image substitutes for the implementation of fully MR-basedradiotherapy and PET/MRI applications.
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| 4. |
- Bayisa, Fekadu, et al.
(författare)
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Statistical learning in computed tomography image estimation
- 2018
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Ingår i: Medical physics (Lancaster). - : John Wiley & Sons. - 0094-2405 .- 2473-4209. ; 45:12, s. 5450-5460
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: There is increasing interest in computed tomography (CT) image estimations from magneticresonance (MR) images. The estimated CT images can be utilized for attenuation correction, patientpositioning, and dose planning in diagnostic and radiotherapy workflows. This study aims to introducea novel statistical learning approach for improving CT estimation from MR images and to compare theperformance of our method with the existing model-based CT image estimation methods.Methods: The statistical learning approach proposed here consists of two stages. At the trainingstage, prior knowledge about tissue types from CT images was used together with a Gaussian mixturemodel (GMM) to explore CT image estimations from MR images. Since the prior knowledge is notavailable at the prediction stage, a classifier based on RUSBoost algorithm was trained to estimatethe tissue types from MR images. For a new patient, the trained classifier and GMMs were used topredict CT image from MR images. The classifier and GMMs were validated by using voxel-leveltenfold cross-validation and patient-level leave-one-out cross-validation, respectively.Results: The proposed approach has outperformance in CT estimation quality in comparison withthe existing model-based methods, especially on bone tissues. Our method improved CT image estimationby 5% and 23% on the whole brain and bone tissues, respectively.Conclusions: Evaluation of our method shows that it is a promising method to generate CTimage substitutes for the implementation of fully MR-based radiotherapy and PET/MRI applications
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| 6. |
- Estévez-Silva, Héctor M., et al.
(författare)
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Pridopidine modifies disease phenotype in a SOD1 mouse model of amyotrophic lateral sclerosis
- 2022
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Ingår i: European Journal of Neuroscience. - : John Wiley & Sons. - 0953-816X .- 1460-9568. ; 55:5, s. 1356-1372
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a lethal and incurable neurodegenerative disease due to the loss of upper and lower motor neurons, which leads to muscle weakness, atrophy, and paralysis. Sigma-1 receptor (σ-1R) is a ligand-operated protein that exhibits pro-survival and anti-apoptotic properties. In addition, mutations in its codifying gene are linked to development of juvenile ALS pointing to an important role in ALS. Here, we investigated the disease-modifying effects of pridopidine, a σ-1R agonist, using a delayed onset SOD1 G93A mouse model of ALS. Mice were administered a continuous release of pridopidine (3.0 mg/kg/day) for 4 weeks starting before the appearance of any sign of muscle weakness. Mice were monitored weekly and several behavioural tests were used to evaluate muscle strength, motor coordination and gait patterns. Pridopidine-treated SOD1 G93A mice showed genotype-specific effects with the prevention of cachexia. In addition, these effects exhibited significant improvement of motor behaviour 5 weeks after treatment ended. However, the survival of the animals was not extended. In summary, these results show that pridopidine can modify the disease phenotype of ALS-associated cachexia and motor deficits in a SOD1 G93A mouse model.
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| 8. |
- Harbs, Justin, et al.
(författare)
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An epigenome-wide analysis of sex hormone levels and DNA methylation in male blood samples
- 2023
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Ingår i: Epigenetics. - : Taylor & Francis Group. - 1559-2294 .- 1559-2308. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Endogenous sex hormones and DNA methylation both play important roles in various diseases. However, their interplay is largely unknown. A deeper understanding of their interrelationships could provide new insights into the pathology of disease development. We, therefore, investigated associations between circulating sex hormones, sex hormone binding globulin (SHBG), and DNA methylation in blood, using samples from 77 men (65 with repeated samples), from the population-based Northern Sweden Health and Disease Study (NSHDS). DNA methylation was measured in buffy coat using the Infinium Methylation EPIC BeadChip (Illumina). Sex hormone (oestradiol, oestrone, testosterone, androstenedione, dehydroepiandrosterone, and progesterone) and SHBG concentrations were measured in plasma using a high-performance liquid chromatography tandem mass spectrometry (LC/MS-MS) method and an enzyme-linked immunoassay, respectively. Associations between sex hormones, SHBG, and DNA methylation were estimated using both linear regression and mixed-effects models. Additionally, we used the comb-p method to identify differentially methylated regions based on nearby P values. We identified one novel CpG site (cg14319657), at which DNA methylation was associated with dehydroepiandrosterone, surpassing a genome-wide significance level. In addition, more than 40 differentially methylated regions were associated with levels of sex hormones and SHBG and several of these mapped to genes involved in hormone-related diseases. Our findings support a relationship between circulating sex hormones and DNA methylation and suggest that further investigation is warranted, both for validation, further exploration and to gain a deeper understanding of the mechanisms and potential consequences for health and disease.
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| 9. |
- Harbs, Justin, 1994-
(författare)
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Circulating markers of risk and etiology in colorectal cancer
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Colorectal cancer is the third most commonly diagnosed cancer in men and women. Worldwide around 2 million individuals are diagnosed each year – a number expected to increase as colorectal cancer risk factors become more prevalent. In men and women there is a difference in incidence, which possibly could be explained by inherent differences, including sex hormone profiles. The prognosis of colorectal cancer is highly dependent on the stage at diagnosis, with individuals diagnosed at early stages having the best long-term survival. However, as onset of symptoms can be diffuse, many individuals are diagnosed at later stages when survival rates are significantly poorer. Therefore, screening and prevention strategies to detect colorectal cancer at earlier stages or remove cancer precursors such as polyps may be key to increasing survival. Commonly used screening tools today include fecal blood tests and colonoscopy, but they have modest accuracy or may not be cost-effective. Being able to identify markers in blood, either for early detection, as a complementary or alternative screening method, or for risk stratification, could aid in solving this problem. Aim: The overall of aim of the thesis was to improve our understanding of underlying factors contributing to CRC etiology and to find biomarkers associated with CRC that could aid in the future development of effective risk prediction models. Methods: All studies included in this thesis were based on a case-control cohort nested within the Northern Sweden Health and Disease Study (NSHDS). Additionally in paper I, we also used data from the European Prospective Investigation into Cancer and Nutrition (EPIC), a large multi-center cohort study. In this paper we examined associations between sex hormones, sex hormone binding globulin (SHBG), and colon cancer in men. The study included 690 colon cancer cases and 690 matched controls. Paper II was a longitudinal study, using repeated samples from 80 men, on circulating sex hormones, SHBG, and DNA methylation in white blood cells. Papers III and IV were nested case-control studies on proteins and colorectal cancer risk with Paper III divided into a discovery and a validation phase. In the first phase, which included 69 colorectal cancer case-control pairs with repeated samples, 160 unique proteins related to inflammation and oncology were analyzed. In the second phase, 13 proteins that were significantly associated with colorectal cancer risk, together with 8 proteins identified from the literature, were measured on a custom panel, and validated in a larger material consisting of 1000 case-control pairs. In paper IV, which included 195 colorectal cancer case-control pairs, the protein analysis was extended to include 1536 proteins linked to oncology, inflammation, neurology, and metabolism. In papers using a matched case-control design, conditional i logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI) for the associations. For longitudinal analyses, mixed effects models were used to estimate associations. Results: In paper I, we observed a statistically significant inverse association between circulating levels of testosterone and colon cancer. For SHBG there was a statistically significant inverse association prior to adjustment of testosterone and estradiol levels. In paper II, we found one novel genome-wide significant association between circulating levels of dehydroepiandrosterone and DNA methylation at the cg14319657 CpG site. In addition, we also identified more than 40 differentially methylated regions associated with levels of sex hormones and SHBG. In paper III, we first identified 13 proteins associated with CRC risk in the discovery phase. In the validation phase, however, none of the proteins remained significantly associated with colorectal cancer. When stratifying by tumor site, FGF-21 and PPY, were statically significant in colon and rectal cancer respectively, and showed some modest increase in predictive performance. In paper IV, we identified 20 proteins surpassing a significance threshold of 0.005. One protein, TFF3 (Trefoil Factor 3), which was positively associated with colorectal, also withstood strict Bonferroni correction. In addition, we validated several proteins, including AREG, CEA, and LGALS4, which were identified as biomarker candidates in previous studies. Conclusions: Our results support the hypothesis that circulating sex hormones play a role in male colon cancer etiology and that this may partly explain the difference in colorectal cancer incidence between men and women. Furthermore, our findings suggest a possible link between circulating sex hormones, SHBG and DNA methylation, which could be of interest in the etiology of colorectal cancer as well as other hormone-dependent diseases. Finally, we also identified several proteins associated with colorectal cancer, some of which have shown potential as screening markers.
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| 10. |
- Harbs, Justin, et al.
(författare)
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Circulating Sex Hormone Levels and Colon Cancer Risk in Men : A Nested Case–Control Study and Meta-Analysis
- 2022
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 31:4, s. 793-803
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Tidskriftsartikel (refereegranskat)abstract
- Background: Endogenous sex hormones may contribute to higher colorectal cancer incidence rates in men compared with women, but despite an increased number of studies, clear evidence is lacking.Methods: We conducted a comprehensive nested case–control study of circulating concentrations of sex hormones, sex hormone precursors, and sex hormone binding globulin (SHBG) in relation to subsequent colon cancer risk in European men. Concentrations were measured using liquid LC/MS-MS in prospectively collected plasma samples from 690 cases and 690 matched controls from the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Northern Sweden Health and Disease Study (NSHDS) cohorts. Multivariable conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). In addition, we conducted a meta-analysis of previous studies on men.Results: Circulating levels of testosterone (OR, 0.68; 95% CI, 0.51–0.89) and SHBG (OR, 0.77; 95% CI, 0.62–0.96) were inversely associated with colon cancer risk. For free testosterone, there was a nonsignificant inverse association (OR, 0.83; 95% CI, 0.58–1.18). In a dose–response meta-analysis of endogenous sex hormone levels, inverse associations with colorectal/colon cancer risk were found for testosterone [relative risks (RR) per 100 ng/dL ¼ 0.98; 95% CI, 0.96–1.00; I2 ¼ 22%] and free testosterone (RR per 1 ng/dL ¼ 0.98; 95% CI, 0.95–1.00; I2 ¼ 0%).Conclusions: Our results provide suggestive evidence for the association between testosterone, SHBG, and male colon cancer development.Impact: Additional support for the involvement of sex hormones in male colon cancer.
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