Characterization of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program

Background

Male breast cancer (BC) is rare, managed by extrapolation from female BC. The International Male BC Program aims to better characterize and manage this disease. We report the results of part I, a retrospective joint analysis of cases diagnosed during a 20-year period.

Methods

Patients with follow-up and tumor samples, treated between 1990 and 2010, in 93 centers/9 countries. Samples were centrally analyzed in three laboratories (the United Kingdom, the Netherlands and the United States).

Results

Of 1822 patients enrolled, 1483 were analyzed; 63.5% were diagnosed between 2001 and 2010, 57 (5.1%) had metastatic disease (M1). Median age at diagnosis: 68.4 years. Of 1054 M0 cases, 56.2% were node-negative (N0) and 48.5% had T1 tumors; 4% had breast conserving surgery (BCS), 18% sentinel lymph-node biopsy; half received adjuvant radiotherapy; 29.8% (neo)adjuvant chemotherapy and 76.8% adjuvant endocrine therapy (ET), mostly tamoxifen (88.4%). Per central pathology, for M0 tumors: 84.8% ductal invasive carcinomas, 51.5% grade 2; 99.3% estrogen receptor (ER)-positive; 81.9% progesterone receptor (PR)-positive; 96.9% androgen receptor (AR)-positive [ER, PR or AR Allred score ≥3]; 61.1% Ki67 expression low (<14% positive cells); using immunohistochemistry (IHC) surrogates, 41.9% were Luminal-A-like, 48.6% Luminal-B-like/HER-2-negative, 8.7% HER-2-positive, 0.3% triple negative. Median follow-up: 8.2 years (0.0-23.8) for all, 7.2 years (0.0-23.2), for M0, 2.6 years (0.0-12.7) for M1 patients. A significant improvement over time was observed in age-corrected BC mortality. BC-specific-mortality was higher for men younger than 50 years. Better overall (OS) and recurrence-free survival (RFS) were observed for highly ER+ (P = 0.001), highly PR+ (P = 0.002), highly AR+ disease (P = 0.019). There was no association between OS/RFS and HER-2 status, Ki67, IHC subtypes nor grade.

Conclusions

Male BC is usually ER, PR and AR-positive, Luminal B-like/HER2-negative. Of note, 56% patients had T1 tumors but only 4% had BCS. ER was highly positive in >90% of cases but only 77% received adjuvant ET. ER, PR and AR were associated with OS and RFS, whereas grade, Ki67 and IHC surrogates were not. Significant improvement in survival over time was observed.

Abstract P6-19-01: Evaluation of multiple transcriptomic gene risk signatures in male breast cancer

Introduction: Male breast cancer (MBC) is a rare disease accounting for less than 1% of all breast cancers (BC) and 1% of all cancers in males. The clinical management is largely extrapolated from female BC. Several multigene assays are increasingly used to guide clinical treatment decisions in female BC, however there is little data on the utility of these tests in MBC.

Methods: Here we present the gene expression results of 380 M0, ER+ve, HER2-ve MBCs enrolled in the Part 1 (retrospective joint analysis) International Male Breast Cancer Program of 1483 patients diagnosed between 1990-2010 (Cardoso et al. Annals of Oncology, 2018). Using a custom Nanostring™ panel comprised of the genes from the commercial risk tests Prosigna®, OncotypeDx® and Mammaprint®, risk scores and intrinsic subtyping data were generated to recapitulate the commercial tests as described by Bayani and Yao et al (npjBreast Cancer, 2017). Survival outcomes by risk classification were analyzed using Cox models with time-dependent covariates when the proportional hazard assumption was not met and adjusted for clinical and treatment variables.

Results: Prosigna-like risk scores identified 99 (26.1%) as low-risk, 159 (41.8%) as intermediate-risk, and 122 (32.1%) as high-risk. Using the TAILORx cut-off (25) for OncotypeDx-like risk of recurrence scoring, 158 (41.6%) were identified as low-risk, while 222 (58.4%) were identified as high-risk. MammaPrint-like results identified 175 (46.1%) as low-risk and 205 (53.9%) as high-risk. Overall, patients classified as high-risk had higher grade, more nodal involvement, larger tumors, and more frequently treated with chemotherapy than low-risk patients. Survival analyses demonstrated clear clinical utility for each test, showing patients at high-risk with poor relapse-free survival (RFS) as compared to patients classified as low-risk: Prosigna-like RFS at 3-years (HR=2.20, 95% CI, 1.28-3.80); Oncotype-like RFS at 3-years (HR=1.92, 95% CI, 1.17-3.17); MammaPrint-like RFS (HR=1.51, 95% CI, 1.00-2.27); with similar findings for distant relapse-free survival (DRFS) and overall survival (OS). Across outcomes and all gene signatures, patients with concordant Low/Low risk classification had better prognosis than those with concordant High/High risk classification. PAM50 intrinsic subtyping identified 147 (38.7%) as Luminal A, 57 (15.0%) as Luminal B, 80 (21.1%) as Her2-enriched and 96 (25.3%) as Basal-like; showing overall 34.5% concordance to clinic-pathological subtyping by central pathology (95% CI, 29.7%-39.5%). Comparison between the tests in the MBC cohort and a comparable cohort of female BC from the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial processed in the same way will be presented.

Conclusion: Common transcriptomic assays designed to assess residual risk, validated in female BC, provide similar information in male BC patients. Not surprisingly, disagreement between test results at the individual patient level was observed. To our knowledge, this is the largest study of MBC assayed to generate risk scores of the current commercial BC tests to demonstrate their clinical utility and their differences and similarity to female BC.

This work has been funded by the Breast Cancer Research Foundation (BCRF).

Citation Format: Bayani J, Poncet C, Yao CQ, Crozier C, Anouk N, Piper T, Cunningham C, Sobol M, Aebi S, Benstead K, Bogler O, Dal Lago L, Fraser J, Hilbers FH, Hedenfalk I, Korde L, Linderholm B, Martens J, Middleton L, Murray M, Kelly C, Nilsson C, Nowaczyk M, Peeters S, Peric A, Porter P, Schröder C, Rubio IT, Ruddy KJ, van Asperen C, Van Den Weyngaert D, van Deurzen C, van Leeuwen-Stok E, Vermeij J, Winer E, Boutros PC, Giordano SH, Cardoso F, Bartlett JM. Evaluation of multiple transcriptomic gene risk signatures in male breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-19-01.

Abstract PD7-12: Molecular subtyping of male breast cancer by the International male breast cancer program (IMBC): EORTC 10085/TBCRC 0-29/BIG 2-07/NABCG/BOOG 2009-04

Introduction. Male breast cancer (male BC) is a rare disease for which disease management is extrapolated from females. IMBC, an international consortium, which previously reported on clinico-pathological aspects, now reports on molecular subgroups revealed by RNA sequencing and their relation to patient outcome.

Methods. Tumor samples from the retrospective MALE BC registry diagnosed between 1990-2010 and with pathology and outcome data (relapse-free- (RFS) and overall survival (OS)) were included (n=699). To allow the discovery of prognostic features, we selected, stratified for known risk factors (TN stage, grade, age at diagnose and adjuvant endocrine treatment), from the cohort 152 cases with poor (RFS &lt;= 4 yrs) and good outcome (RFS &gt; 7yrs) evenly distributed. Here, we report RNA sequencing results of the first 73 cases, 38 with poor and 35 with good outcome. RNA sequencing reads were used to generate gene expression values and to report transcripts carrying driver mutations. Unsupervised clustering identified subgroups and within subgroups differentially expressed genes were identified. The reported prognostic male BC subgroups M1 and M2 (Johansson BCR 2012(14):R31) were also annotated. All identified subgroups were related to outcome using logistic regression (p-value using Wald test).

Results. Unsupervised clustering revealed 2 main subgroups of which group 1 was enriched for expression of ER target genes, WNT3 and genes from amplicons known for female BC, e.g. 19p13 (CCNE1), 8q24 (MYC), and 11q13 (CCND1). The biology of the smaller group 2 was less defined but TGFβ2 expression was high as were various kallikreins (KLK) including interestingly KLK3 (prostate specific antigen). Other known amplified regions [(8p11 (FGFR1), 20q13 (ZNF217) and 12q15 (MDM2)] and mutated transcripts [PIK3CA (H1047R/L/Q; E542K, E545K, N345K; 16% of cases), TP53 and SF3B1 (K700E) (2% of cases)] were identified. Profound tumor infiltrate gene expression was present in 5% of cases and one third of cases expressed proliferation markers. Except for TP53, none of these latter characteristics were unevenly distributed among the 2 main subgroups. ER and AR were highly correlated, particularly in group 1. The two main groups could be further subdivided. Group 1 comprised 3 subgroups of which subgroup 1a expressed TFF1/3 and NAT1, well-known ER targets, while subgroups 1b and 1c expressed other ER targets,respectively BEX1 and PITX1. HOXC cluster expression differentiated subgroup 1b from 1a and 1c. None of these intrinsic subgroups were, however, related to RFS. The previously reported M2 subgroup, which largely segregated with subclusters 1a and 1b, was associated with a better RFS than the M1 subgroup (OR=2.9; 95%CI 1.1-7.5; p-value=0.03).

Conclusions. 1) Intrinsic subtypes of male BC were revealed and their subgrouping is defined by ER associated subsets of genes. 2) The association of the reported M2 subgroup of male BC with longer RFS was validated; 3) Currently identified biological characteristics of male BC may improve future treatments. The full report on 152 cases including a comparison to female BC will be presented at the conference.

This research was funded by Breast Cancer Research Foundation

Citation Format: Martens JWM, Sieuwerts A, Ponchet C, Smid M, de Weerd V, Slaets L, Piper T, van Deurzen CHM, Schroder CP, Stangle C, Kloosterman W, van Leeuwen-Stok E, Nilsson C, Vermeij J, Peeters S, Goulioti T, Nowaczyk M, Aebi S, Rubio IT, Kelly C, Bayani J, Porter P, Murray M, Hudis C, Middleton L, Korde L, Ruddy K, Winer E, Bogler O, van den Weyngaert D, dal Lago L, Fraser J, Benstead K, van Asperen C, Linderholm B, Hedenfalk I, Tryfonidis K, Giordano S, Bartlett J, Cardoso F. Molecular subtyping of male breast cancer by the International male breast cancer program (IMBC): EORTC 10085/TBCRC 0-29/BIG 2-07/NABCG/BOOG 2009-04 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD7-12.

Genetics of vascular dementia - review from the ICVD working group

BACKGROUND

Vascular dementia is a common disorder resulting in considerable morbidity and mortality. Determining the extent to which genes play a role in disease susceptibility and their pathophysiological mechanisms could improve our understanding of vascular dementia, leading to a potential translation of this knowledge to clinical practice.

DISCUSSION

In this review, we discuss what is currently known about the genetics of vascular dementia. The identification of causal genes remains limited to monogenic forms of the disease, with findings for sporadic vascular dementia being less robust. However, progress in genetic research on associated phenotypes, such as cerebral small vessel disease, Alzheimer's disease, and stroke, have the potential to inform on the genetics of vascular dementia. We conclude by providing an overview of future developments in the field and how such work could impact patients and clinicians.

CONCLUSION

The genetic background of vascular dementia is well established for monogenic disorders, but remains relatively obscure for the sporadic form. More work is needed for providing robust findings that might eventually lead to clinical translation.

Associations between TOMM40 Poly-T Repeat Variants and Dementia in Cases with Parkinsonism

BACKGROUND

Mitochondrial dysfunction has been implicated in the pathophysiology of Parkinson's disease (PD)-related pathologies.

OBJECTIVE

To investigate the role of the Translocase of the Outer Mitochondrial Membrane 40 homolog (TOMM40) variants in PD without dementia (PDND), PD with dementia (PDD) and in Dementia with Lewy bodies (DLB).

METHODS

248 individuals, including 92 PDND, 55 PDD, and 101 DLB, were included. The rs10524523 locus in the TOMM40 gene (TOMM40 poly-T repeat) is characterized by a variable number of T residues that were classified into three groups based on length; short (S), long (L), and very long (VL). We tested log-additive genetic model of association with dementia and adjusted for age, sex, and APOEɛ4 carrier status. We analyzed cerebrospinal fluid (CSF) levels of Aβ42 and Tau, biomarkers related to Alzheimer's disease (AD).

RESULTS

PDD/DBL status and abnormal CSF AD biomarkers (Aβ42 and Aβ42/Tau ratio) were both associated with the APOEɛ4 allele (p <  0.014) and the L allele of TOMM40 poly-T repeat (p <  0.008). The VL allele was less frequently observed in the PDD/DLB group (p = 0.013). In APOE-ɛ4 adjusted analyses, the relationships between the L and VL alleles and dementia status as well as CSF AD biomarkers were not significant. When adjusting for APOE-ɛ4, however, there were associations between S carrier status and PDD/DLB (p = 0.019) and abnormal CSF levels of Aβ42/Tau ratio (p = 0.037) although these were not significant after adjustment for multiple comparisons.

CONCLUSION

Our results do not support the notion that TOMM40 poly-T repeat variants have independent effects on PDD and DLB pathology. This relationship seems to be driven by APOE-ɛ4.

Physical activity and risk of Amyotrophic Lateral Sclerosis in a prospective cohort study

Previous case-control studies have suggested a possible increased risk of Amyotrophic Lateral Sclerosis (ALS) with physical activity (PA), but this association has never been studied in prospective cohort studies. We therefore assessed the association between PA and risk of death from ALS in the European Prospective Investigation into Cancer and Nutrition. A total of 472,100 individuals were included in the analysis, yielding 219 ALS deaths. At recruitment, information on PA was collected thorough standardised questionnaires. Total PA was expressed by the Cambridge Physical Activity Index (CPAI) and analysed in relation to ALS mortality, using Cox hazard models. Interactions with age, sex, and anthropometric measures were assessed. Total PA was weakly inversely associated with ALS mortality with a borderline statistically significant trend across categories (p = 0.042), with those physically active being 33% less likely to die from ALS compared to those inactive: HR = 0.67 (95% CI 0.42-1.06). Anthropometric measures, sex, and age did not modify the association with CPAI. The present study shows a slightly decreased-not increased like in case-control studies-risk of dying from ALS in those with high levels of total PA at enrolment. This association does not appear confounded by age, gender, anthropometry, smoking, and education. Ours was the first prospective cohort study on ALS and physical activity.

Parkinson's Disease Case Ascertainment in the EPIC Cohort: The NeuroEPIC4PD Study

BACKGROUND/AIMS

Large epidemiological prospective studies represent an important opportunity for investigating risk factors for rare diseases such as Parkinson's disease (PD). Here we describe the procedures we used for ascertaining PD cases in the EPIC (European Prospective Investigation into Cancer and Nutrition) study.

METHODS

The following three-phase procedure was used: (1) elaboration of a NeuroEPIC4PD template for clinical data collection, (2) identification of all potential PD cases via record linkage and (3) validation of the diagnosis through clinical record revision, in a population of 220,494 subjects recruited in 7 European countries. All cases were labelled with the NeuroEPIC4PD diagnoses of 'definite', 'very likely', 'probable', or 'possible' PD.

RESULTS

A total of 881 PD cases were identified, with over 2,741,780 person-years of follow-up (199 definite, 275 very likely, 146 probable, and 261 possible). Of these, 734 were incident cases. The mean age at diagnosis was 67.9 years (SD 9.2) and 458 patients (52.0%) were men. Bradykinesia was the most frequent presenting motor sign (76.5%). Tremor-dominant and akinetic rigid forms of PD were the most common types of PD. A total of 289 patients (32.8%) were dead at the time of the last follow-up.

CONCLUSIONS

This exercise proved that it is feasible to ascertain PD in large population-based cohort studies and offers a potential framework to be replicated in similar studies.

Joint analysis of psychiatric disorders increases accuracy of risk prediction for schizophrenia, bipolar disorder, and major depressive disorder

Genetic risk prediction has several potential applications in medical research and clinical practice and could be used, for example, to stratify a heterogeneous population of patients by their predicted genetic risk. However, for polygenic traits, such as psychiatric disorders, the accuracy of risk prediction is low. Here we use a multivariate linear mixed model and apply multi-trait genomic best linear unbiased prediction for genetic risk prediction. This method exploits correlations between disorders and simultaneously evaluates individual risk for each disorder. We show that the multivariate approach significantly increases the prediction accuracy for schizophrenia, bipolar disorder, and major depressive disorder in the discovery as well as in independent validation datasets. By grouping SNPs based on genome annotation and fitting multiple random effects, we show that the prediction accuracy could be further improved. The gain in prediction accuracy of the multivariate approach is equivalent to an increase in sample size of 34% for schizophrenia, 68% for bipolar disorder, and 76% for major depressive disorders using single trait models. Because our approach can be readily applied to any number of GWAS datasets of correlated traits, it is a flexible and powerful tool to maximize prediction accuracy. With current sample size, risk predictors are not useful in a clinical setting but already are a valuable research tool, for example in experimental designs comparing cases with high and low polygenic risk.

Relationship between obesity and the risk of clinically significant depression: Mendelian randomisation study

BACKGROUND

Obesity has been shown to be associated with depression and it has been suggested that higher body mass index (BMI) increases the risk of depression and other common mental disorders. However, the causal relationship remains unclear and Mendelian randomisation, a form of instrumental variable analysis, has recently been employed to attempt to resolve this issue.

AIMS

To investigate whether higher BMI increases the risk of major depression.

METHOD

Two instrumental variable analyses were conducted to test the causal relationship between obesity and major depression in RADIANT, a large case-control study of major depression. We used a single nucleotide polymorphism (SNP) in FTO and a genetic risk score (GRS) based on 32 SNPs with well-established associations with BMI.

RESULTS

Linear regression analysis, as expected, showed that individuals carrying more risk alleles of FTO or having higher score of GRS had a higher BMI. Probit regression suggested that higher BMI is associated with increased risk of major depression. However, our two instrumental variable analyses did not support a causal relationship between higher BMI and major depression (FTO genotype: coefficient -0.03, 95% CI -0.18 to 0.13, P = 0.73; GRS: coefficient -0.02, 95% CI -0.11 to 0.07, P = 0.62).

CONCLUSIONS

Our instrumental variable analyses did not support a causal relationship between higher BMI and major depression. The positive associations of higher BMI with major depression in probit regression analyses might be explained by reverse causality and/or residual confounding.

Development and validation of a risk score predicting substantial weight gain over 5 years in middle-aged European men and women

Background

Identifying individuals at high risk of excess weight gain may help targeting prevention efforts at those at risk of various metabolic diseases associated with weight gain. Our aim was to develop a risk score to identify these individuals and validate it in an external population.

Methods

We used lifestyle and nutritional data from 53°758 individuals followed for a median of 5.4 years from six centers of the European Prospective Investigation into Cancer and Nutrition (EPIC) to develop a risk score to predict substantial weight gain (SWG) for the next 5 years (derivation sample). Assuming linear weight gain, SWG was defined as gaining ≥10% of baseline weight during follow-up. Proportional hazards models were used to identify significant predictors of SWG separately by EPIC center. Regression coefficients of predictors were pooled using random-effects meta-analysis. Pooled coefficients were used to assign weights to each predictor. The risk score was calculated as a linear combination of the predictors. External validity of the score was evaluated in nine other centers of the EPIC study (validation sample).

Results

Our final model included age, sex, baseline weight, level of education, baseline smoking, sports activity, alcohol use, and intake of six food groups. The model's discriminatory ability measured by the area under a receiver operating characteristic curve was 0.64 (95% CI = 0.63–0.65) in the derivation sample and 0.57 (95% CI  = 0.56–0.58) in the validation sample, with variation between centers. Positive and negative predictive values for the optimal cut-off value of ≥200 points were 9% and 96%, respectively.

Conclusion

The present risk score confidently excluded a large proportion of individuals from being at any appreciable risk to develop SWG within the next 5 years. Future studies, however, may attempt to further refine the positive prediction of the score.

Epidemiology of Alzheimer's disease and other forms of dementia in China, 1990-2010: a systematic review and analysis

BACKGROUND

China is increasingly facing the challenge of control of the growing burden of non-communicable diseases. We assessed the epidemiology of Alzheimer's disease and other forms of dementia in China between 1990, and 2010, to improve estimates of the burden of disease, analyse time trends, and inform health policy decisions relevant to China's rapidly ageing population.

METHODS

In our systematic review we searched for reports of Alzheimer's disease or dementia in China, published in Chinese and English between 1990 and 2010. We searched China National Knowledge Infrastructure, Wanfang, and PubMed databases. Two investigators independently assessed case definitions of Alzheimer's disease and dementia: we excluded studies that did not use internationally accepted case definitions. We also excluded reviews and viewpoints, studies with no numerical estimates, and studies not done in mainland China. We used Poisson regression and UN demographic data to estimate the prevalence (in nine age groups), incidence, and standardised mortality ratio of dementia and its subtypes in China in 1990, 2000, and 2010.

FINDINGS

Our search returned 12,642 reports, of which 89 met the inclusion criteria (75 assessed prevalence, 13 incidence, and nine mortality). In total, the included studies had 340,247 participants, in which 6357 cases of Alzheimer's disease were recorded. 254,367 people were assessed for other forms of dementia, of whom 3543 had vascular dementia, frontotemporal dementia, or Lewy body dementia. In 1990 the prevalence of all forms of dementia was 1·8% (95% CI 0·0-44·4) at 65-69 years, and 42·1% (0·0-88·9) at age 95-99 years. In 2010 prevalence was 2·6% (0·0-28·2) at age 65-69 years and 60·5% (39·7-81·3) at age 95-99 years. The number of people with dementia in China was 3·68 million (95% CI 2·22-5·14) in 1990, 5·62 million (4·42-6·82) in 2000, and 9·19 million (5·92-12·48) in 2010. In the same period, the number of people with Alzheimer's disease was 1·93 million (1·15-2·71) in 1990, 3·71 million (2·84-4·58) people in 2000, and 5·69 million (3·85-7·53) in 2010. The incidence of dementia was 9·87 cases per 1000 person-years, that of Alzheimer's disease was 6·25 cases per 1000 person-years, that of vascular dementia was 2·42 cases per 1000 person-years, and that of other rare forms of dementia was 0·46 cases per 1000 person-years. We retrieved mortality data for 1032 people with dementia and 20,157 healthy controls, who were followed up for 3-7 years. The median standardised mortality ratio was 1·94:1 (IQR 1·74-2·45).

INTERPRETATION

Our analysis suggests that previous estimates of dementia burden, based on smaller datasets, might have underestimated the burden of dementia in China. The burden of dementia seems to be increasing faster than is generally assumed by the international health community. Rapid and effective government responses are needed to tackle dementia in low-income and middle-income countries.

FUNDING

Nossal Institute of Global Health (University of Melbourne, Australia), the National 12th Five-Year Major Projects of China, National Health and Medical Research Council Australia-China Exchange Fellowship, Importation and Development of High-Calibre Talents Project of Beijing Municipal Institutions, and the Bill & Melinda Gates Foundation.

A mega-analysis of genome-wide association studies for major depressive disorder

Prior genome-wide association studies (GWAS) of major depressive disorder (MDD) have met with limited success. We sought to increase statistical power to detect disease loci by conducting a GWAS mega-analysis for MDD. In the MDD discovery phase, we analyzed more than 1.2 million autosomal and X chromosome single-nucleotide polymorphisms (SNPs) in 18 759 independent and unrelated subjects of recent European ancestry (9240 MDD cases and 9519 controls). In the MDD replication phase, we evaluated 554 SNPs in independent samples (6783 MDD cases and 50 695 controls). We also conducted a cross-disorder meta-analysis using 819 autosomal SNPs with P<0.0001 for either MDD or the Psychiatric GWAS Consortium bipolar disorder (BIP) mega-analysis (9238 MDD cases/8039 controls and 6998 BIP cases/7775 controls). No SNPs achieved genome-wide significance in the MDD discovery phase, the MDD replication phase or in pre-planned secondary analyses (by sex, recurrent MDD, recurrent early-onset MDD, age of onset, pre-pubertal onset MDD or typical-like MDD from a latent class analyses of the MDD criteria). In the MDD-bipolar cross-disorder analysis, 15 SNPs exceeded genome-wide significance (P<5 × 10(-8)), and all were in a 248 kb interval of high LD on 3p21.1 (chr3:52 425 083-53 822 102, minimum P=5.9 × 10(-9) at rs2535629). Although this is the largest genome-wide analysis of MDD yet conducted, its high prevalence means that the sample is still underpowered to detect genetic effects typical for complex traits. Therefore, we were unable to identify robust and replicable findings. We discuss what this means for genetic research for MDD. The 3p21.1 MDD-BIP finding should be interpreted with caution as the most significant SNP did not replicate in MDD samples, and genotyping in independent samples will be needed to resolve its status.

Prediagnostic body fat and risk of death from amyotrophic lateral sclerosis: the EPIC cohort

OBJECTIVES

The aim of this study was to investigate for the first time the association between body fat and risk of amyotrophic lateral sclerosis (ALS) with an appropriate prospective study design.

METHODS

The EPIC (European Prospective Investigation into Cancer and Nutrition) study included 518,108 individuals recruited from the general population across 10 Western European countries. At recruitment, information on lifestyle was collected and anthropometric characteristics were measured. Cox hazard models were fitted to investigate the associations between anthropometric measures and ALS mortality.

RESULTS

Two hundred twenty-two ALS deaths (79 men and 143 women) occurred during the follow-up period (mean follow-up = 13 years). There was a statistically significant interaction between categories of body mass index and sex regarding ALS risk (p = 0.009): in men, a significant linear decrease of risk per unit of body mass index was observed (hazard ratio = 0.93, 95% confidence interval 0.86-0.99 per kg/m(2)); among women, the risk was more than 3-fold increased for underweight compared with normal-weight women. Among women, a significant risk reduction increasing the waist/hip ratio was also evident: women in the top quartile had less than half the risk of ALS compared with those in the bottom quartile (hazard ratio = 0.48, 95% confidence interval 0.25-0.93) with a borderline significant p value for trend across quartiles (p = 0.056).

CONCLUSION

Increased prediagnostic body fat is associated with a decreased risk of ALS mortality.

A genome-wide significant linkage for severe depression on chromosome 3: the depression network study

OBJECTIVE

The purpose of this study was to find loci for major depression via linkage analysis of a large sibling pair sample.

METHOD

The authors conducted a genome-wide linkage analysis of 839 families consisting of 971 affected sibling pairs with severe recurrent major depression, comprising waves I and II of the Depression Network Study cohort. In addition to examining affected status, linkage analyses in the full data set were performed using diagnoses restricted by impairment severity, and association mapping of hits in a large case-control data set was attempted.

RESULTS

The authors identified genome-wide significant linkage to chromosome 3p25-26 when the diagnoses were restricted by severity, which was a maximum LOD score of 4.0 centered at the linkage marker D3S1515. The linkage signal identified was genome-wide significant after correction for the multiple phenotypes tested, although subsequent association mapping of the region in a genome-wide association study of a U.K. depression sample did not provide significant results.

CONCLUSIONS

The authors report a genome-wide significant locus for depression that implicates genes that are highly plausible for involvement in the etiology of recurrent depression. Despite the fact that association mapping in the region was negative, the linkage finding was replicated by another group who found genome-wide-significant linkage for depression in the same region. This suggests that 3p25-26 is a new locus for severe recurrent depression. This represents the first report of a genome-wide significant locus for depression that also has an independent genome-wide significant replication.