| 11. |
- Li, Jingmei, et al.
(författare)
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Breast cancer genetic risk profile is differentially associated with interval and screen-detected breast cancers
- 2015
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Ingår i: Annals of Oncology. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0923-7534. ; 26:3, s. 517-522
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Tidskriftsartikel (refereegranskat)abstract
- Background: Polygenic risk profiles computed from multiple common susceptibility alleles for breast cancer have been shown to identify women at different levels of breast cancer risk. We evaluated whether this genetic risk stratification can also be applied to discriminate between screen-detected and interval cancers, which are usually associated with clinicopathological and survival differences. Patients and methods: A 77-SNP polygenic risk score (PRS) was constructed for breast cancer overall and by estrogen-receptor (ER) status. PRS was inspected as a continuous (per standard deviation increment) variable in a case-only design. Modification of the PRS by mammographic density was evaluated by fitting an additional interaction term. Results: PRS weighted by breast cancer overall estimates was found to be differentially associated with 1,865 screen-detected and 782 interval cancers in the LIBRO-1 study (age-adjusted ORperSD [95% confidence interval]=0.91 [0.83-0.99], p=0.023). The association was found to be more significant for PRS weighted by ER-positive breast cancer estimates (ORperSD=0.90 [0.82-0.98], p=0.011). This result was corroborated by two independent studies (combined ORperSD=0.87 [0.76-1.00], p=0.058) with no evidence of heterogeneity. When enriched for “true” interval cancers among nondense breasts, the difference in the association with PRS in screen-detected and interval cancers became more pronounced (ORperSD=0.74 [0.62-0.89], p=0.001), with a significant interaction effect between PRS and mammographic density (pinteraction=0.017). Conclusion: To our knowledge, this is the first report looking into the genetic differences between screendetected and interval cancers. It is an affirmation that the two types of breast cancer may have unique underlying biology.
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| 12. |
- Li, Jinhai, et al.
(författare)
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Effects of Roadway Segment Alignments and Locations on Rural Two-Lane Highway Crash Rates
- 2013
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Ingår i: Proceedings of the 16th International Conference Road Safety on Four Continents. - Linköping : Statens väg- och transportforskningsinstitut.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper investigates the effects of road segment alignment and location on rural two-lane highway crash rates by taking the mileage of segment types into consideration. Roadway segments are classified and redefined according to the segment alignment and location. The definitions of crash rates in terms of segment alignment and location are presented respectively. The study gathers crash data and the roadway geometric information of rural two-lane highways in southwest of China and crash rates of each segment type are proposed by utilizing the proposed definitions. The result indicates that gentle-slope & sharp-curve segments and intersections tend to have extremely higher crash rates than the other types of segments.
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| 13. |
- Li, Jingmei
(författare)
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Genetic determinants of breast cancer risk
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of this thesis was to identify genetic risk factors using both hypothesis-based and hypothesis-free approaches. In an attempt to identify common disease susceptibility alleles for breast cancer, we started off with a hypothesis-free approach, and performed a combined analysis of three genome-wide association studies (GWAS), involving 2,702 women of European ancestry with invasive breast cancer and 5,726 controls. As GWAS has been said to underperform for studying complex diseases such as breast cancer, we investigated to see if the variance explained by common variants could be increased by studying specific disease subtypes. Breast cancer may be characterized on the basis of whether estrogen receptors (ER) are expressed in the tumour cells. The two breast cancer tumour subtypes (ER-positive and ER- negative) are generally considered as biologically distinct diseases and have been associated with remarkably different gene expression profiles. ER status is important clinically, and is used both as a prognosticator and treatment predictor since it determines if a patient may benefit from anti-estrogen therapy. We thus performed an independent GWAS using a subset of ER-negative breast cancer cases and all of the controls from the initial genome-wide study, and, in addition, also evaluated whether the two cancer subtypes are fundamentally different on a germline level. Besides hypothesis-free GWAS, we also conducted hypothesis-based analyses based on candidate pathways to identify common variants associated with breast cancer. Several studies have examined the effect of genetic variants in genes involved in the estrogen metabolic pathway on mammographic density, but the number of loci studied and the sample sizes evaluated have been small and pathways have not been evaluated comprehensively. We evaluated a total of 239 SNPs in 34 genes in the estrogen metabolic pathway in 1,731 Swedish women who participated in a breast cancer case-control study. Slightly venturing outside the genetic scope of this thesis, we looked at a breast cancer risk factor - body size - that is associated with very different postmenopausal breast cancer risks at different time points in a woman’s lifetime, namely, birth, childhood, and postmenopausal adult. The significance of these studies will be apparent when, using the new genetic and epidemiological knowledge found, we are able to classify women according to high or low risk of breast cancer on the basis of genetic disposition or other breast cancer risk factors, so that appropriate interventions and disease management decisions may be made, to ultimately reduce incidence and mortality of breast cancer.
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| 14. |
- Li, Jingmei, et al.
(författare)
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Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort
- 2019
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 144:5, s. 1195-1204
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer patients with BRCA1/2-driven tumors may benefit from targeted therapy. It is not clear whether current BRCA screening guidelines are effective at identifying these patients. The purpose of our study was to evaluate the prevalence of inherited BRCA1/2 pathogenic variants in a large, clinically representative breast cancer cohort and to estimate the proportion of BRCA1/2 carriers not detected by selectively screening individuals with the highest probability of being carriers according to current clinical guidelines. The study included 5,122 unselected Swedish breast cancer patients diagnosed from 2001 to 2008. Target sequence enrichment (48.48 Fluidigm Access Arrays) and sequencing were performed (Illumina Hi-Seq 2,500 instrument, v4 chemistry). Differences in patient and tumor characteristics of BRCA1/2 carriers who were already identified as part of clinical BRCA1/2 testing routines and additional BRCA1/2 carriers found by sequencing the entire study population were compared using logistic regression models. Ninety-two of 5,099 patients with valid variant calls were identified as BRCA1/2 carriers by screening all study participants (1.8%). Only 416 study participants (8.2%) were screened as part of clinical practice, but this identified 35 out of 92 carriers (38.0%). Clinically identified carriers were younger, less likely postmenopausal and more likely to be associated with familiar ovarian cancer compared to the additional carriers identified by screening all patients. More BRCA2 (34/42, 81.0%) than BRCA1 carriers (23/50, 46%) were missed by clinical screening. In conclusion, BRCA1/2 mutation prevalence in unselected breast cancer patients was 1.8%. Six in ten BRCA carriers were not detected by selective clinical screening of individuals.
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| 15. |
- Ma, Xin, et al.
(författare)
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[CH3NH3][M(HCOO)3]-based 2D porous NiCo2S4 nanosheets for high-performance supercapacitors with high power densities
- 2022
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 437
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Tidskriftsartikel (refereegranskat)abstract
- Cost-effective and high-performance electrode materials for energy storage and conversion are essential for commercial applications. In this work, the influence of solvent on the morphologies of [CH3NH3][M(HCOO)3] precursors was studied to design and synthesize two-dimensional (2D) porous NiCo2S4 nanosheets with different structures. As an electrode material for supercapacitors, Microflower-NiCo2S4 exhibits excellent capacitance (1,141 F g−1 at 1 A g−1) and stability (88.2% of initial capacitance maintained after 5,000 cycles at 5 A g−1). Moreover, an asymmetric capacitor was constructed using Microflower-NiCo2S4 and porous carbon (PC) and demonstrated an energy density of 51.25 Wh kg−1 at a power density of 397.5 W kg−1. When two Microflower-NiCo2S4//PC asymmetric supercapacitors were assembled in series, the device supplied power for an alarm clock with dimensions of 6.1 × 6.1 cm2 for more than 32 min. Therefore, the preparation of metal sulfides and metal oxides with hollow structures using a [CH3NH3][M(HCOO)3]-template has potential applications in energy storage and conversion.
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| 16. |
- Mavaddat, Nasim, et al.
(författare)
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Prediction of Breast Cancer Risk Based on Profiling With Common Genetic Variants
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 107:5, s. 036-036
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Tidskriftsartikel (refereegranskat)abstract
- Background: Data for multiple common susceptibility alleles for breast cancer may be combined to identify women at different levels of breast cancer risk. Such stratification could guide preventive and screening strategies. However, empirical evidence for genetic risk stratification is lacking. Methods: We investigated the value of using 77 breast cancer-associated single nucleotide polymorphisms (SNPs) for risk stratification, in a study of 33 673 breast cancer cases and 33 381 control women of European origin. We tested all possible pair-wise multiplicative interactions and constructed a 77-SNP polygenic risk score (PRS) for breast cancer overall and by estrogen receptor (ER) status. Absolute risks of breast cancer by PRS were derived from relative risk estimates and UK incidence and mortality rates. Results: There was no strong evidence for departure from a multiplicative model for any SNP pair. Women in the highest 1% of the PRS had a three-fold increased risk of developing breast cancer compared with women in the middle quintile (odds ratio [OR] = 3.36, 95% confidence interval [CI] = 2.95 to 3.83). The ORs for ER-positive and ER-negative disease were 3.73 (95% CI = 3.24 to 4.30) and 2.80 (95% CI = 2.26 to 3.46), respectively. Lifetime risk of breast cancer for women in the lowest and highest quintiles of the PRS were 5.2% and 16.6% for a woman without family history, and 8.6% and 24.4% for a woman with a first-degree family history of breast cancer. Conclusions: The PRS stratifies breast cancer risk in women both with and without a family history of breast cancer. The observed level of risk discrimination could inform targeted screening and prevention strategies. Further discrimination may be achievable through combining the PRS with lifestyle/environmental factors, although these were not considered in this report.
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| 17. |
- Mueller, Stefanie H., et al.
(författare)
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Aggregation tests identify new gene associations with breast cancer in populations with diverse ancestry
- 2023
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Ingår i: Genome Medicine. - : BioMed Central (BMC). - 1756-994X .- 1756-994X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Low-frequency variants play an important role in breast cancer (BC) susceptibility. Gene-based methods can increase power by combining multiple variants in the same gene and help identify target genes.Methods: We evaluated the potential of gene-based aggregation in the Breast Cancer Association Consortium cohorts including 83,471 cases and 59,199 controls. Low-frequency variants were aggregated for individual genes' coding and regulatory regions. Association results in European ancestry samples were compared to single-marker association results in the same cohort. Gene-based associations were also combined in meta-analysis across individuals with European, Asian, African, and Latin American and Hispanic ancestry.Results: In European ancestry samples, 14 genes were significantly associated (q < 0.05) with BC. Of those, two genes, FMNL3 (P = 6.11 x 10(-6)) and AC058822.1 (P = 1.47 x 10(-4)), represent new associations. High FMNL3 expression has previously been linked to poor prognosis in several other cancers. Meta-analysis of samples with diverse ancestry discovered further associations including established candidate genes ESR1 and CBLB. Furthermore, literature review and database query found further support for a biologically plausible link with cancer for genes CBLB, FMNL3, FGFR2, LSP1, MAP3K1, and SRGAP2C.Conclusions: Using extended gene-based aggregation tests including coding and regulatory variation, we report identification of plausible target genes for previously identified single-marker associations with BC as well as the discovery of novel genes implicated in BC development. Including multi ancestral cohorts in this study enabled the identification of otherwise missed disease associations as ESR1 (P = 1.31 x 10(-5)), demonstrating the importance of diversifying study cohorts.
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| 18. |
- Shum, Jingmei Li, et al.
(författare)
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Perturbation-induced droplets for manipulating droplet structure and configuration in microfluidics
- 2015
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Ingår i: Journal of Micromechanics and Microengineering. - 0960-1317 .- 1361-6439. ; 25:8
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we mechanically perturb a liquid-in-liquid jet to manipulate the size and structure of the droplets formed from break-up of the jet. The induced break-up is relatively insensitive to fluctuations in the surrounding fluid flow. When the amplitude of perturbations is large and the interfacial tension of the liquid–liquid system is low, the size of the droplets can be precisely tuned by controlling the rate at which the liquid exits the tip of the dispensing nozzle through the frequency of perturbation. When applied to microfluidic devices with the appropriate geometry, our perturbation-induced droplet approach offers a strategy to manipulating droplet structures. We demonstrate that by varying the imposed perturbation frequency and phase lag, the structure of the multi-compartmental drops and the configuration of the resultant drops in the same flow condition can be manipulated. Moreover, after careful treatment of the wettability of the devices, we show that the structure of the droplets can be precisely controlled to change from single emulsion to double emulsion within the same device. The perturbation-induced droplet generation represents a new paradigm in the engineering of droplets, enhancing current droplet-based technologies for applications ranging from particle fabrication to confined micro-reactions.
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| 19. |
- Strand, Fredrik, et al.
(författare)
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Longitudinal fluctuation in mammographic percent density differentiates between interval and screen-detected breast cancer
- 2016
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Ingår i: International Journal of Cancer. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0020-7136 .- 1097-0215.
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Tidskriftsartikel (refereegranskat)abstract
- Interval breast cancer (IC) has a more aggressive phenotype and higher mortality than screen-detected cancer (SDC). In this case-case study, we investigated whether the size of longitudinal fluctuations in mammographic percent density (PD fluctuation) was associated with the ratio of IC versus SDC among screened women with breast cancer. The primary study population consisted of 1,414 postmenopausal breast cancer cases, and the validation population of 1,241 cases. We calculated PD fluctuation as the quadratic mean of deviations between actual PD and the long-term trend estimated by a mixed effects model. In a logistic regression model we examined the association between PD fluctuation and IC versus SDC including adjustments for PD at last screening, age at diagnosis, BMI and hormone replacement therapy. All statistical tests were two-sided. There were 385 IC and 1,029 SDC in the primary study population, with PD fluctuations of 0.44 and 0.41 respectively (p = 0.0309). After adjustments, PD fluctuation was associated with an increased ratio of IC versus SDC, with an estimated per-standard deviation odds ratio of 1.17 (95% CI = 1.03-1.33), compared to 1.19 (95% CI = 1.04-1.38) in the validation population. In screened women with breast cancer, high fluctuation in mammographic percent density was associated with an increased ratio of IC versus SDC. Whether this is entirely related to a reduced mammographic detectability or to a biological phenotype promoting faster tumor growth remains to be elucidated.
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| 20. |
- Ugalde-Morales, Emilio, et al.
(författare)
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Association between breast cancer risk and disease aggressiveness : Characterizing underlying gene expression patterns
- 2021
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 148:4, s. 884-894
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Tidskriftsartikel (refereegranskat)abstract
- The association between breast cancer risk defined by the Tyrer-Cuzick score (TC) and disease prognosis is not well established. Here, we investigated the relationship between 5-year TC and disease aggressiveness and then characterized underlying molecular processes. In a case-only study (n = 2474), we studied the association of TC with molecular subtypes and tumor characteristics. In a subset of patients (n = 672), we correlated gene expression to TC and computed a low-risk TC gene expression (TC-Gx) profile, that is, a profile expected to be negatively associated with risk, which we used to test for association with disease aggressiveness. We performed enrichment analysis to pinpoint molecular processes likely to be altered in low-risk tumors. A higher TC was found to be inversely associated with more aggressive surrogate molecular subtypes and tumor characteristics (P <.05) including Ki-67 proliferation status (P < 5 × 10−07). Our low-risk TC-Gx, based on the weighted sum of 37 expression values of genes strongly correlated with TC, was associated with basal-like (P < 5 × 10−13), HER2-enriched subtype (P < 5 × 10−07) and worse 10-year breast cancer-specific survival (log-rank P < 5 × 10−04). Associations between low-risk TC-Gx and more aggressive molecular subtypes were replicated in an independent cohort from The Cancer Genome Atlas database (n = 975). Gene expression that correlated with low TC was enriched in proliferation and oncogenic signaling pathways (FDR < 0.05). Moreover, higher proliferation was a key factor explaining the association with worse survival. Women who developed breast cancer despite having a low risk were diagnosed with more aggressive tumors and had a worse prognosis, most likely driven by increased proliferation. Our findings imply the need to establish risk factors associated with more aggressive breast cancer subtypes.
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