| 1. |
- Sampson, Joshua N., et al.
(author)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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In: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Journal article (peer-reviewed)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 2. |
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- 2019
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Journal article (peer-reviewed)
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| 3. |
- Tabar, Laszlo, et al.
(author)
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Effect of Mammography Screening on Mortality by Histological Grade
- 2018
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In: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 27:2, s. 154-157
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Journal article (peer-reviewed)abstract
- Background: It has been asserted that mammography screening preferentially benefits those with less aggressive cancers, with lesser or no impact on more rapidly progressing and therefore more life-threatening tumors. Methods: We utilized data from the Swedish Two-County Trial, which randomized 77,080 women ages 40 to 74 to invitation to screening and 55,985 for usual care. We tabulated cancers by histologic grade and then compared mortality from cancers specific to histologic grade between the invited and control group using Poisson regression, with specific interest in the effect on mortality from grade 3 cancers. We used incidence-based mortality from tumors diagnosed within the screening phase of the trial. Finally, we cross-tabulated grade with tumor size and node status, to assess downstaging within tumor grades. Results: There was a major reduction in mortality from grade 3 tumors (RR = 0.65; 95% CI, 0.53-0.80; P < 0.001), and more deaths prevented from grade 3 tumors (n = 95) than grade 1 and 2 tumors combined (n = 48) in the invited group. The proportions of tumors >= 15 mm or larger and node-positive tumors were substantially reduced in the grade 3 tumors in the invited group. Conclusions: The combination of prevention of tumors progressing to grade 3 and detection at smaller sizes and lesser rates of lymph node metastases within grade 3 tumors results in a substantial number of deaths from grade 3 cancers being prevented by invitation to mammographic screening. Impact: Mammography screening prevents deaths from aggressive cancers.
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| 4. |
- Chen, M-J, et al.
(author)
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Body mass index and breast cancer : analysis of a nation-wide population-based prospective cohort study on 1 393 985 Taiwanese women
- 2016
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In: International Journal of Obesity. - : Springer Science and Business Media LLC. - 0307-0565 .- 1476-5497. ; 40:3, s. 524-530
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Journal article (peer-reviewed)abstract
- BACKGROUND: Asian women have a younger age at onset of breast cancer and a lower body mass index (BMI) than Western women. The link between obesity and risk of breast cancer in Asian women is still elusive. We aimed to investigate the effect of BMI on the risk of incident breast cancer in Taiwanese women.METHODS: A total of 1 393 985 women who had been cancer-free before recruitment and attended a nation-wide Taiwanese breast cancer-screening program between 1999 and 2009 were enrolled using a prospective cohort study. Obesity and other relevant variables (such as menopause status and other biochemical markers) were collected through in-person interviews, anthropometric measurements and blood samples at first screen. Incident breast cancers during follow-up were ascertained through the linkage of the cohort with the National Cancer Registry and the National Death Certification System.RESULTS: A total of 6969 and 7039 incident breast cancer cases were identified among women enrolled before and after menopause, respectively. Compared with a BMI range of 18.5-23.9 kgm(-2), the incremental level of BMI in the enrolled women before menopause revealed a lack of statistically significant association with the risk of incident breast cancer (adjusted hazard ratio = 0.94, 0.98, 1.02, 1.01 and 0.82 for BMI < 18.5, 24-26.9, 27-29.9, 30-34.9 and >= 35, respectively), but the incremental level of BMI in the enrolled women after menopause led to a statistically significant incremental increase in the risk of breast cancer (adjusted hazard ratio = 0.78, 1.19, 1.31, 1.53 and 1.65 for BMI < 18.5, 24-26.9, 27-29.9, 30-34.9 and >= 35, respectively) after adjusting for other explanatory risk factors.CONCLUSION: Obesity acts mainly as an influential promoter of the development of late-onset breast cancer after menopause in Taiwanese women.
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| 5. |
- Kabat, G. C., et al.
(author)
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Metabolic phenotypes of obesity : frequency, correlates and change over time in a cohort of postmenopausal women
- 2017
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In: International Journal of Obesity. - : Springer Science and Business Media LLC. - 0307-0565 .- 1476-5497. ; 41:1, s. 170-177
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Journal article (peer-reviewed)abstract
- Objective: The possibility that a subset of persons who are obese may be metabolically healthy—referred to as the ‘metabolically healthy obese’ (MHO) phenotype—has attracted attention recently. However, few studies have followed individuals with MHO or other obesity phenotypes over time to assess change in their metabolic profiles. The aim of the present study was to examine transitions over a 6-year period among different states defined simultaneously by body mass index (BMI) and the presence/absence of the metabolic syndrome (MetS).Methods: We used repeated measurements available for a subcohort of participants enrolled in the Women’s Health Initiative (N=3512) and followed for an average of 6 years to examine the frequency of different metabolic obesity phenotypes at baseline, the 6-year transition probabilities to other states and predictors of the risk of different transitions. Six phenotypes were defined by cross-tabulating BMI (18.5–<25.0, 25.0–<30.0, 30.0 kg m−2) by MetS (yes, no). A continuous-time Markov model was used to estimate 6-year transition probabilities from one state to another.Results: Over the 6 years of follow-up, one-third of women with the healthy obese phenotype transitioned to the metabolically unhealthy obese (MUO) phenotype. Overall, there was a marked tendency toward increased metabolic deterioration with increasing BMI and toward metabolic improvement with lower BMI. Among MHO women, the 6-year probability of becoming MUO was 34%, whereas among unhealthy normal-weight women, the probability of ‘regressing’ to the metabolically healthy normal-weight phenotype was 52%.Conclusions: The present study demonstrated substantial change in metabolic obesity phenotypes over a 6-year period. There was a marked tendency toward metabolic deterioration with greater BMI and toward metabolic improvement with lower BMI.
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| 6. |
- Sjöberg, Rickard L, et al.
(author)
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Role of monoamine-oxidase-A-gene variation in the development of glioblastoma in males : a case control study
- 2019
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In: Journal of Neuro-Oncology. - : Springer. - 0167-594X .- 1573-7373. ; 145:2, s. 287-294
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Journal article (peer-reviewed)abstract
- Background: The Mono-amine oxidase-A (MAO-A) enzyme is involved in the degradation and regulation of catecholamines such as serotonin, dopamine, epinephrine and nor-epinephrine. Preclinical studies suggest that this enzyme may contribute to an environment favorable for growth of malignant glioma. The MAO-A gene is located on the X-chromosome and has at least one functional genetic polymorphism. The aim of the present study was to explore possible effects of MAO-A genotype on development of glioblastoma in males.Methods: Genotypes for 437 glioma cases and 876 population-based controls from the Swedish Glioma International Case–Control study (GICC) were compared. We analyzed the germline DNA using the Illumina Oncoarray. We selected seven single nucleotide polymorphisms (SNPs) located in the MAO-A gene, and imputed genotypes based on data from the 1000 genomes project. We used 1579 male glioblastoma cases and 1875 controls comprising the whole GICC cohort for subsequent validation of findings.Results: The rs144551722 SNP was a significant predictor of development of glioblastoma in males (p-value = 0.0056) but not in females even after correction for multiple testing. We conducted haplotype analysis to confirm an association between MAO-A gene and risk of glioblastoma (p-value = 0.016). We found similar results in the validation sample.Conclusions: These results suggest the possibility of a role for the MAO-A enzyme and the MAO-A gene in the development of glioblastoma in males.
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| 7. |
- Tabár, László, et al.
(author)
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Evaluation issues in the Swedish Two-County Trial of breast cancer screening : An historical review
- 2017
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In: Journal of Medical Screening. - : SAGE PUBLICATIONS LTD. - 0969-1413 .- 1475-5793. ; 24:1, s. 27-33
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Journal article (peer-reviewed)abstract
- Objectives: To summarize debate and research in the Swedish Two-County Trial of mammographic screening on key issues of trial design, endpoint evaluation, and overdiagnosis, and from these to infer promising directions for the future. Methods: A cluster-randomized controlled trial of the offer of breast cancer screening in Sweden, with a single screen of the control group at the end of the screening phase forms the setting for a historical review of investigations and debate on issues of design, analysis, and interpretation of results of the trial. Results: There has been considerable commentary on the closure screen of the control group, ascertainment of cause of death, and cluster randomization. The issues raised were researched in detail and the main questions answered in publications between 1989 and 2003. Overdiagnosis issues still remain, but methods of estimation taking full account of lead time and of nonscreening influences on incidence (taking place mainly before 2005) suggest that it is a minor phenomenon. Conclusion: Despite resolution of issues relating to this trial in peer-reviewed publications dating from years, or even decades ago, issues that already have been addressed continue to be raised. We suggest that it would be more profitable to concentrate efforts on current research issues in breast cancer diagnosis, treatment, and prevention.
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| 8. |
- Tabar, Laszlo, et al.
(author)
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The incidence of fatal breast cancer measures the increased effectiveness of therapy in women participating in mammography screening
- 2019
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In: Cancer. - : John Wiley & Sons. - 0008-543X .- 1097-0142. ; 125:4, s. 515-523
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Journal article (peer-reviewed)abstract
- Background: Women and their health care providers need a reliable answer to this important question: If a woman chooses to participate in regular mammography screening, then how much will this choice improve her chances of avoiding a death from breast cancer compared with women who choose not to participate? Methods: To answer this question, we used comprehensive registries for population, screening history, breast cancer incidence, and disease-specific death data in a defined population in Dalarna County, Sweden. The annual incidence of breast cancer was calculated along with the annual incidence of breast cancers that were fatal within 10 and within 11 to 20 years of diagnosis among women aged 40 to 69 years who either did or did not participate in mammography screening during a 39-year period (1977-2015). For an additional comparison, corresponding data are presented from 19 years of the prescreening period (1958-1976). All patients received stage-specific therapy according to the latest national guidelines, irrespective of the mode of detection. Results: The benefit for women who chose to participate in an organized breast cancer screening program was a 60% lower risk of dying from breast cancer within 10 years after diagnosis (relative risk, 0.40; 95% confidence interval, 0.34-0.48) and a 47% lower risk of dying from breast cancer within 20 years after diagnosis (relative risk, 0.53; 95% confidence interval, 0.44-0.63) compared with the corresponding risks for nonparticipants. Conclusions: Although all patients with breast cancer stand to benefit from advances in breast cancer therapy, the current results demonstrate that women who have participated in mammography screening obtain a significantly greater benefit from the therapy available at the time of diagnosis than do those who have not participated.
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| 9. |
- Wu, Wendy Yi-Ying, et al.
(author)
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Imaging Biomarkers as Predictors for Breast Cancer Death
- 2019
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In: Journal of Oncology. - : Hindawi Publishing Corporation. - 1687-8450 .- 1687-8469.
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Journal article (peer-reviewed)abstract
- Background. To differentiate the risk of breast cancer death in a longitudinal cohort using imaging biomarkers of tumor extent and biology, specifically, the mammographic appearance, basal phenotype, histologic tumor distribution, and conventional tumor attributes. Methods. Using a prospective cohort study design, 498 invasive breast cancer patients diagnosed between 1996 and 1998 were used as the test cohort to assess the independent effects of the imaging biomarkers and other predictors on the risk of breast cancer death. External validation was performed with a cohort of 848 patients diagnosed between 2006 and 2010. Results. Mammographic tumor appearance was an independent predictor of risk of breast cancer death (P=0.0003) when conventional tumor attributes and treatment modalities were controlled. The casting type calcifications and architectural distortion were associated with 3.13-fold and 3.19-fold risks of breast cancer death, respectively. The basal phenotype independently conferred a 2.68-fold risk compared with nonbasal phenotype. The observed deaths did not differ significantly from expected deaths in the validation cohort. The application of imaging biomarkers together with other predictors classified twelve categories of risk for breast cancer death. Conclusion. Combining imaging biomarkers such as the mammographic appearance of the tumor with the histopathologic distribution and basal phenotype, accurately predicted long-term risk of breast cancer death. The information may be relevant for determining the need for molecular testing, planning treatment, and determining the most appropriate clinical surveillance schedule for breast cancer patients.
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| 10. |
- Wu, Wendy Yi-Ying, et al.
(author)
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Overdiagnosis in the population-based organized breast cancer screening program estimated by a non-homogeneous multi-state model : a cohort study using individual data with long-term follow-up
- 2018
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In: Breast Cancer Research. - : BioMed Central. - 1465-5411 .- 1465-542X. ; 20
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Journal article (peer-reviewed)abstract
- Background: Overdiagnosis, defined as the detection of a cancer that would not become clinically apparent in a woman’s lifetime without screening, has become a growing concern. Similar underlying risk of breast cancer in the screened and control groups is a prerequisite for unbiased estimates of overdiagnosis, but a contemporary control group is usually not available in organized screening programs.Methods: We estimated the frequency of overdiagnosis of breast cancer due to screening in women 50–69 years old by using individual screening data from the population-based organized screening program in Stockholm County 1989–2014. A hidden Markov model with four latent states and three observed states was constructed to estimate the natural progression of breast cancer and the test sensitivity. Piecewise transition rates were used to consider the time-varying transition rates. The expected number of detected non-progressive breast cancer cases was calculated.Results: During the study period, 2,333,153 invitations were sent out; on average, the participation rate in the screening program was 72.7% and the average recall rate was 2.48%. In total, 14,648 invasive breast cancer cases were diagnosed; among the 8305 screen-detected cases, the expected number of non-progressive breast cancer cases was 35.9, which is equivalent to 0.43% (95% confidence interval (CI) 0.10%–2.2%) overdiagnosis. The corresponding estimates for the prevalent and subsequent rounds were 15.6 (0.87%, 95% CI 0.20%–4.3%) and 20.3 (0.31%, 95% CI 0.07%–1.6%), respectively. The likelihood ratio test showed that the non-homogeneous model fitted the data better than an age-homogeneous model (P<0.001).Conclusions: Our findings suggest that overdiagnosis in the organized biennial mammographic screening for women 50–69 in Stockholm County is a minor phenomenon. The frequency of overdiagnosis in the prevalent screening round was higher than that in subsequent rounds. The non-homogeneous model performed better than the simpler, traditional homogeneous model.
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