| 1. |
- Svensson, J. Peter, et al.
(författare)
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Analysis of gene expression using gene sets discriminates cancer patients with and without late radiation toxicity
- 2006
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Ingår i: PLoS Medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 3:10, s. 1904-1914
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Tidskriftsartikel (refereegranskat)abstract
- Background Radiation is an effective anti-cancer therapy but leads to severe late radiation toxicity in 5%-10% of patients. Assuming that genetic susceptibility impacts this risk, we hypothesized that the cellular response of normal tissue to X-rays could discriminate patients with and without late radiation toxicity. Methods and Findings Prostate carcinoma patients without evidence of cancer 2 y after curative radiotherapy were recruited in the study. Blood samples of 21 patients with severe late complications from radiation and 17 patients without symptoms were collected. Stimulated peripheral lymphocytes were mock-irradiated or irradiated with 2-Gy X-rays. The 24-h radiation response was analyzed by gene expression profiling and used for classification. Classification was performed either on the expression of separate genes or, to augment the classification power, on gene sets consisting of genes grouped together based on function or cellular colocalization. X- ray irradiation altered the expression of radio-responsive genes in both groups. This response was variable across individuals, and the expression of the most significant radio-responsive genes was unlinked to radiation toxicity. The classifier based on the radiation response of separate genes correctly classified 63% of the patients. The classifier based on affected gene sets improved correct classification to 86%, although on the individual level only 21/38 (55%) patients were classified with high certainty. The majority of the discriminative genes and gene sets belonged to the ubiquitin, apoptosis, and stress signaling networks. The apoptotic response appeared more pronounced in patients that did not develop toxicity. In an independent set of 12 patients, the toxicity status of eight was predicted correctly by the gene set classifier. Conclusions Gene expression profiling succeeded to some extent in discriminating groups of patients with and without severe late radiotherapy toxicity. Moreover, the discriminative power was enhanced by assessment of functionally or structurally related gene sets. While prediction of individual response requires improvement, this study is a step forward in predicting susceptibility to late radiation toxicity.
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| 2. |
- Själander, Sara, et al.
(författare)
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Assessment of Use vs Discontinuation of Oral Anticoagulation After Pulmonary Vein Isolation in Patients With Atrial Fibrillation
- 2017
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Ingår i: JAMA cardiology. - : American Medical Association. - 2380-6583 .- 2380-6591. ; 2:2, s. 146-152
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: Pulmonary vein isolation (PVI) is a recommended treatment for patients with atrial fibrillation, but it is unclear whether it results in a lower risk of stroke.OBJECTIVES: To investigate the proportion of patients discontinuing anticoagulation treatment after PVI in association with the CHA(2)DS(2)-VASc (congestive heart failure, hypertension, age >= 75 years [doubled], diabetes, stroke [doubled], vascular disease, age 65-74 years, sex category [female]) score, identify factors predicting stroke after PVI, and explore the risk of cardiovascular events after PVI in patients with and without guideline-recommended anticoagulation treatment.DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort studywas conducted using Swedish national health registries from January 1, 2006, to December 31, 2012, with a mean-follow up of 2.6 years. A total of 1585 patients with atrial fibrillation undergoing PVI from the Swedish Catheter Ablation Register were included, with information about exposure to warfarin in the national quality register Auricula. Data analysis was performed from January 1, 2015, to April 30, 2016.EXPOSURES: Warfarin treatment.MAIN OUTCOMES AND MEASURES: Ischemic stroke, intracranial hemorrhage, and death.RESULTS: In this cohort of 1585 patients, 73.0% were male, the mean (SD) age was 59.0 (9.4) years, and the mean (SD) CHA(2)DS(2)-VASc score was 1.5 (1.4). Of the 1585 patients, 1175 were followed up for more than 1 year after PVI. Of these, 360 (30.6%) discontinued warfarin treatment during the first year. In patients with a CHA(2)DS(2)-VASc score of 2 or more, patients discontinuing warfarin treatment had a higher rate of ischemic stroke (5 events in 312 years at risk [1.6% per year]) compared with those continuing warfarin treatment (4 events in 1192 years at risk [0.3% per year]) (P = .046). Patients with a CHA(2)DS(2)-VASc score of 2 or more or those who had previously experienced an ischemic stroke displayed a higher risk of stroke if warfarin treatment was discontinued (hazard ratio, 4.6; 95% CI, 1.2-17.2; P = .02 and hazard ratio, 13.7; 95% CI, 2.0-91.9; P = .007, respectively).CONCLUSIONS AND RELEVANCE: These findings indicate that discontinuation ofwarfarin treatment after PVI is not safe in high-risk patients, especially those who have previously experienced an ischemic stroke.
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| 3. |
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| 4. |
- Ahmad, Abrar, et al.
(författare)
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Alpha 2-macroglobulin 5 bp insertion/deletion polymorphism increases the risk of recurrent venous thromboembolism
- 2018
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Ingår i: Gene Reports. - : Elsevier BV. - 2452-0144. ; 13, s. 104-109
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Tidskriftsartikel (refereegranskat)abstract
- Alpha 2-macroglobulin (A2M) is a protease inhibitor that has been reported to neutralize thrombin, which may decrease the risk of thrombosis. A 5-base pairs (bp) insertion/deletion polymorphism (rs3832852) at the splice acceptor site of exon 18 has been shown to affect the binding of A2M with proteases. However, the role of this important variant in A2M in recurrent VTE is unknown. We investigated the role of 5 bp insertion/deletion polymorphism in VTE recurrence in a follow up study. A2M 5 bp insertion/deletion polymorphism was genotyped in Malmö Thrombophilia Study (MATS, n = 1465, with follow up of ~10 years) by TaqMan Allelic Discrimination assay. Univariate Cox regression analysis showed that A2M polymorphism was significantly associated with higher risk of VTE recurrence (hazard ratio [HR] = 2.61, 95% confidence interval [CI] = 1.06–6.45, P = 0.037). This association remained significant (HR = 2.61, 95% CI = 1.06–6.47, P = 0.038) even after adjusting for sex, family history of VTE, thrombophilia and acquired risk factors for VTE. In conclusion, our results indicate that patients with A2M 5 bp insertion/deletion polymorphism are at significantly higher risk of VTE recurrence and this may predict VTE recurrence.
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| 5. |
- Ahmad, Abrar, et al.
(författare)
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Association between TLR9 rs5743836 polymorphism and risk of recurrent venous thromboembolism
- 2017
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Ingår i: Journal of Thrombosis and Thrombolysis. - : Springer Science and Business Media LLC. - 1573-742X .- 0929-5305. ; 44:1, s. 130-138
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Tidskriftsartikel (refereegranskat)abstract
- Recent gene knockout studies on mice have shown the role of toll-like receptor 9 (TLR9) in resolution of venous thromboembolism (VTE) through sterile inflammation. However, the role of a putative functional TLR9 polymorphism (rs5743836) in risk assessment of VTE recurrence remains unknown. The aim of our study was to investigate the TLR9 rs5743836 polymorphism in VTE patients and its association with the risk of VTE recurrence. We analyzed TLR9 rs5743836 polymorphism in Malmö thrombophilia study patients; a prospective follow-up study of 1465 VTE patients by Taqman PCR. From a total of 1465 VTE patients, those who had VTE before inclusion and those who died or had VTE recurrence during anticoagulant treatment were excluded (n = 415). Cox regression analyses were performed on the remaining 1050 VTE patients, including 126 (12.5%) patients that had recurrent VTE during follow-up period. TLR9 polymorphism was significantly associated with higher risk of VTE recurrence in female patients (HR 3.46, 95% CI 1.06-11.33) independent of acquired risk factors for VTE, family history, risk of thrombophilia and deep vein thrombosis (DVT) location. Similarly, in unprovoked VTE patients, TLR9 polymorphism was significantly associated with higher risk of VTE recurrence in female patients (HR 5.94, 95% CI 1.25-28.13) after adjusting for family history, risk of thrombophilia and DVT location. No association between TLR9 polymorphism and risk of VTE recurrence was found in male patients. Our results suggest that TLR9 rs5743836 polymorphism is an independent risk factor for VTE recurrence in female patients but not in males.
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| 6. |
- Ahmad, Abrar, et al.
(författare)
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Evaluation of Expression Level of Apolipoprotein M as a Diagnostic Marker for Primary Venous Thromboembolism
- 2018
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Ingår i: Clinical and Applied Thrombosis/Hemostasis. - : SAGE Publications. - 1938-2723 .- 1076-0296. ; 24:3, s. 416-422
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Tidskriftsartikel (refereegranskat)abstract
- Recently, decreased levels of apolipoprotein M (ApoM) were shown to be associated with higher risk of recurrent venous thromboembolism (VTE) in male patients. However, the role of ApoM in primary VTE is unknown. We aimed in our study to analyze the plasma levels of ApoM in patients with VTE in order to evaluate the diagnostic importance of ApoM in primary VTE. A total of 357 patients with suspected first episode of VTE were recruited prospectively in the SCORE study. Plasma samples from 307 patients were available for quantifying the plasma levels of ApoM in patients with VTE using sandwich enzyme-linked immunosorbent assay method. Among the whole population, plasma levels (mean [standard deviation]) of ApoM were not significantly different between patients with VTE (0.72 [0.20]) and non-VTE patients (0.72 [0.16]), P = .99. Similarly, in regression analyses, no significant association of ApoM plasma levels with the risk of VTE was found on univariate (odds ratio [OR] =1.0, 95% confidence interval [CI] 0.21-4.84, P = .99) and multivariate analysis (OR = 1.25, 95% CI = 0.19-8.34, P = .819) after adjusting for age, body mass index, and smoking. Moreover, results did not differ significantly after stratification of data according to sex ( P > .05). In this study, our results do not suggest a diagnostic role for ApoM plasma levels in patients with primary VTE. Moreover, the current study suggests that role of ApoM as a risk factor may differ for primary VTE and recurrent VTE in male patients.
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| 7. |
- Ahmad, Abrar, et al.
(författare)
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Fat mass and obesity-associated gene rs9939609 polymorphism is a potential biomarker of recurrent venous thromboembolism in male but not in female patients
- 2018
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Ingår i: Gene. - : Elsevier BV. - 0378-1119. ; 647, s. 136-142
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Tidskriftsartikel (refereegranskat)abstract
- Multiple genetic variations have been identified in FTO (fat mass and obesity-associated) gene. Among them, FTO rs9939609 polymorphism is shown to be associated with the risk of primary venous thromboembolism (VTE). However, its role in recurrent VTE is not known. The aim of our study was to investigate the association between FTO rs9939609 polymorphism and the risk of VTE recurrence in a prospective follow-up study in both male and female patients. FTO rs9939609 polymorphism (T/A) was analyzed in the Malmö thrombophilia study (MATS, followed for ~10 years) by using TaqMan PCR. MATS patients (n = 1050) were followed from the discontinuation of anticoagulant treatment until diagnosis of VTE recurrence or the end of follow-up. A total of 126 patients (12%) had VTE recurrence during follow-up. Cox regression analyses showed that sex modified the potential effect of FTO rs9939609 polymorphism on VTE recurrence. Male patients with the AA genotype for the FTO rs9939609 polymorphism had significantly higher risk of VTE recurrence as compared to the TT or AT genotypes (univariate hazard ratio [HR] = 2.05, 95% confidence interval [CI] = 1.2-3.5, P = 0.009 and adjusted HR = 2.03, 95% CI 1.2-3.6, P = 0.013). There was no association between FTO rs9939609 polymorphism and VTE recurrence in female patients. In conclusion, our results show that FTO rs9939609 polymorphism in recurrent VTE may differ according to gender and FTO polymorphism may predict VTE recurrence in male patients.
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| 8. |
- Ahmad, Abrar, et al.
(författare)
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Identification of Genetic Aberrations in Thrombomodulin Gene in Patients with Recurrent Venous Thromboembolism
- 2017
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Ingår i: Clinical and Applied Thrombosis/Hemostasis. - : SAGE Publications. - 1076-0296 .- 1938-2723. ; 23:4, s. 319-328
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Tidskriftsartikel (refereegranskat)abstract
- Thrombomodulin (THBD) serves as a cofactor for thrombin-mediated activation of anticoagulant protein C pathway. Genetic aberrations in THBD have been studied in arterial and venous thrombosis. However, genetic changes in THBD and their role in the risk assessment of recurrent venous thromboembolism (VTE) are not well understood. The aim of the present study was to identify the genetic aberrations in THBD and their association with the risk of VTE recurrence in a prospective population-based study. We sequenced the entire THBD gene, first in selected patients with VTE (n = 95) by Sanger sequencing and later validated those polymorphisms with minor allele frequency (MAF) ≥5% in the whole study population (n = 1465 with the follow-up period of 1998-2008) by Taqman polymerase chain reaction. In total, we identified 8 polymorphisms in THBD, and 3 polymorphisms with MAF ≥5% were further validated. No significant association between THBD polymorphisms and risk of VTE recurrence on univariate or multivariate Cox regression analysis was found (hazard ratio [HR] = 0.89, 95% confidence interval [CI] = 0.62-1.28, HR = 1.27, 95% CI = 0.88-1.85, and HR = 1.15, 95% CI = 0.80-1.66 for THBD rs1962, rs1042580, and rs3176123 polymorphisms, respectively), adjusted for family history, acquired risk factors for VTE, location of deep vein thrombosis, and risk of thrombophilia. Subanalysis of patients with unprovoked first VTE also showed no significant association of identified THBD polymorphisms with the risk of VTE recurrence. Our results show that aberrations in the THBD gene may not be useful for the assessment of VTE recurrence; however, further studies with large sample size are needed to confirm these findings.
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| 9. |
- Ahmad, Abrar, et al.
(författare)
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Identification of polymorphisms in Apolipoprotein M gene and their relationship with risk of recurrent venous thromboembolism
- 2016
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Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 116:3, s. 41-432
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (ApoM) plasma levels have been reported to be associated with risk of venous thromboembolism (VTE) recurrence. However, the role of genetic alterations in the ApoM gene in VTE recurrence remains unknown. The aim of this study was to identify genetic aberrations in ApoM gene in VTE recurrence and their role in prediction of VTE recurrence in a prospective follow-up study of 1465 VTE patients. During follow-up, 156 (10.6 %) patients had VTE recurrence. First screening of whole ApoM gene was performed by Sanger's sequencing in selected age and sex matched non-recurrent and recurrent patients (n=95). In total six polymorphisms were identified and two polymorphisms (rs805297 and rs9404941) with minor allele frequency (MAF) ≥5 % were further genotyped in the whole cohort by Taqman PCR. ApoM rs805297 polymorphism was significantly associated with higher risk of VTE recurrence in males but not in females on both univariate (p= 0.038, hazard ratio = 1.72, confidence interval = 1.03-2.88) and on multivariate analysis adjusted with mild and severe thrombophilia, family history, location and acquired risk factors for VTE. However, ApoM rs9404941 polymorphism showed no significant association with risk of VTE recurrence in all patients as well as in different gender groups. Moreover, ApoM rs805297 and rs9404941 polymorphisms were not associated with the ApoM plasma levels. In conclusion, for the first time we have sequenced whole ApoM gene in VTE and identified six polymorphisms. ApoM rs805297 was significantly associated with higher risk of VTE recurrence in male but not in female patients.
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| 10. |
- Ahmad, Abrar, et al.
(författare)
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Risk prediction of recurrent venous thromboembolism : a multiple genetic risk model
- 2019
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Ingår i: Journal of Thrombosis and Thrombolysis. - : Springer Science and Business Media LLC. - 0929-5305 .- 1573-742X. ; 47:2, s. 216-226
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Tidskriftsartikel (refereegranskat)abstract
- A single genetic biomarker is unable to accurately predict the risk for venous thromboembolism (VTE) recurrence. We aimed to: (a) develop a multiple single nucleotide polymorphisms (SNPs) model to predict the risk of VTE recurrence and (b) validate a previously described genetic risk score (GRS) and compare its performance with the model developed in this study. Twenty-two SNPs, including established and putative SNPs associated with VTE risk, were genotyped in the Malmö thrombophilia study cohort (MATS; n = 1465, follow-up ~ 10 years) by using TaqMan PCR. Out of 22-SNPs, 12 had an association with the risk of VTE recurrence and were included for calculating GRSs. The risk of VTE recurrence was calculated by stratifying patients according to number of risk alleles. In 12-SNP GRS, patients with ≥ 7 risk alleles were associated with higher risk of VTE recurrence compared to patients having ≤ 6 risk alleles. In a simplified model (8-SNP GRS), the discriminative power of 8-SNP GRS was similar to that of 12-SNP GRS based on post-test probabilities (PP). Furthermore, 8-SNP GRS further improved the risk prediction of VTE recurrence in unprovoked VTE and male patients (PP% = 15.4 vs 8.3, 17.1 vs 7.2 and 19.0 vs 7.1 for high risk groups vs low risk groups in whole population, males and unprovoked VTE patients respectively). In addition, we also validated previously described 5-SNP GRS in our cohort and found that the 8-SNP GRS performed better than the 5-SNP GRS in terms of higher PP. Our results show that a multiple SNP GRS consisting of 8-SNPs may be an effective model for prediction of VTE recurrence, particularly in unprovoked VTE and male patients.
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