Incidence of clinically diagnosed psoriatic arthritis in Sweden.

OBJECTIVE: Prior incidence estimates of psoriatic arthritis (PsA) vary considerably. We aimed to assess the annual incidence of clinically diagnosed PsA among adults in Sweden 2014-2016, overall and stratified by age/sex/education/geography, and to investigate potential time-trends in incidence 2006-2018. Disease-modifying anti-rheumatic drug (DMARD) use during 2 years (y) from diagnosis was also examined. METHODS: Patients (≥18y) with incident clinically diagnosed PsA in Sweden were identified from the National Patient Register (NPR) and/or the Swedish Rheumatology Quality register (SRQ). Population statistics, stratification parameters and DMARD information were retrieved from other nationwide registers. Incidence was estimated according to a base case (BC) definition (i.e., ≥1 main ICD-10 diagnosis of PsA [L40.5/M07.0-M07.3] from rheumatology/internal medicine in NPR, or a PsA diagnosis in SRQ during the relevant year, and no prior such diagnoses) and four different sensitivity analysis case definitions. RESULTS: The mean annual incidence of clinically diagnosed PsA among adults in Sweden 2014-2016 was estimated at 21.77/100 000 person-years at risk (PY), according to the BC definition; 17.41/100 000 PY after accounting for diagnostic misclassification; and 15.78-28.83/100 000 PY across all sensitivity analyses. Incidence was slightly higher in females, lower in individuals with higher education (>12y) and peaked in the age-span 50-59y. No apparent increasing/decreasing time-trend was observed 2006-2018. Within 2y from diagnosis, 71.03% of patients had received DMARD-therapy (22.37% biologic/targeted synthetic DMARDs). CONCLUSION: During 2014-2016, the annual incidence of clinically diagnosed PsA in the adult Swedish population was around 20/100 000 PY. Two years after diagnosis, almost 3/4 had received DMARD-therapy.

Mortality in patients with psoriatic arthritis in Sweden: a nationwide, population-based cohort study.

OBJECTIVES: To compare all-cause mortality and causes of death between patients with psoriatic arthritis (PsA) and the general population in Sweden. METHODS: Adults with at least one main PsA diagnosis (International Classification of Diseases-10: L40.5/M07.0-M07.3) from outpatient rheumatology/internal medicine departments 2001-2017 were identified from the National Patient Register. Each case was matched to five population comparator-subjects on sex/county/age at the case's first arthritis diagnosis. Follow-up ran from 1 January 2007, or from first PsA diagnosis thereafter, until death, emigration or 31 December 2018. Mortality was assessed overall, and stratified by sex and duration since diagnosis (diagnosis before/after 1 January 2007), using matched Cox proportional hazard regression (excluding/including adjustments for comorbidity) or Breslow test, as appropriate. Incidence rate ratios (IRR) of death, overall and stratified by sex/duration since diagnosis/age, as well as causes of death in PsA cases and comparator-subjects were also described. RESULTS: All-cause mortality was elevated in PsA (HR: 1.11 (95% CI: 1.07 to 1.16); IRR: 1.18 (95% CI: 1.13 to 1.22)), mainly driven by increased risks in women (HR: 1.23 (95% CI: 1.16 to 1.30)) and cases with longer time since diagnosis (HR: 1.18 (95% CI: 1.12 to 1.25)). IRR of death were significantly increased for all ages except below 40 years, with the numerically highest point-estimates for ages 40-59 years. When adjusted for comorbidity, however, the elevated mortality risk in PsA disappeared. Causes of death were similar among PsA cases/comparator-subjects, with cardiovascular disease and malignancy as the leading causes. CONCLUSIONS: Mortality risk in PsA in Sweden was about 10% higher than in the general population, driven by excess comorbidity and with increased risks mainly in women and patients with longer disease duration.

The National Prevalence of Clinically Diagnosed Psoriatic Arthritis in Sweden in 2017.

OBJECTIVE: Psoriatic arthritis (PsA) prevalence estimates vary across studies; studies based on national data are few. We aimed to estimate the prevalence of clinically diagnosed PsA in Sweden in 2017, overall and stratified by sex, age, education, and geography, and to quantify disease-modifying antirheumatic drug (DMARD) use among those in contact with specialized rheumatology care between 2015 and 2017. METHODS: Individuals who were 18 to 79 years of age, alive and residing in Sweden on December 31, 2017, and had a prior PsA diagnosis were identified from the National Patient Register (NPR) and/or the Swedish Rheumatology Quality Register (SRQ). PsA prevalence was estimated according to a base case (BC) definition (ie, ≥ 1 main PsA International Classification of Diseases code from rheumatology or internal medicine departments in the NPR or a PsA diagnosis in the SRQ), according to 4 sensitivity analysis definitions, and for those seen in specialized rheumatology care between 2015 and 2017. In the latter group, DMARD use during 2017 was also assessed. Data for stratifications were retrieved from national registers. RESULTS: The crude national prevalence of PsA for adults, aged 18 to 79 years, was estimated at 0.39%, according to the BC definition; 0.34% after accounting for diagnostic misclassification; and 0.32% to 0.50% across all sensitivity analyses. The prevalence was lower in males and in those with a higher level of education. The prevalence for those seen in specialized rheumatology care between 2015 and 2017 was estimated at 0.24%. During 2017, 32% of patients in this population received biologic or targeted synthetic DMARDs, and 41% received conventional synthetic DMARDs only. CONCLUSION: The prevalence of clinically diagnosed PsA in adults, aged 18 to 79 years, in Sweden in 2017 was around 0.35%. Among PsA cases in recent contact with specialized rheumatology care, almost three-fourths received DMARD therapy in 2017.

Biological treatment of ankylosing spondylitis: a nationwide study of treatment trajectories on a patient level in clinical practice.

BACKGROUND: There is substantial evidence that patients with ankylosing spondylitis (AS) have high response rates to tumour necrosis factor inhibitors (TNFi), a low likelihood of successful treatment termination, but yet a limited drug retention. Whereas several reports have assessed drug retention rates for TNFi in AS, there are few, if any, studies investigating the actual treatment trajectories on a patient level, including subsequent therapy changes and dose reductions, of individual patients. The aim of this study was to describe 5-year treatment trajectories in patients with ankylosing spondylitis (AS) starting a first TNFi. METHODS: Bio-naïve patients with AS starting a TNFi in 2006-2015 were identified in the nationwide Swedish Rheumatology Quality register and followed until 31 December 2015. All changes in their anti-rheumatic treatment during follow-up were recorded. To further increase precision, these data were complimented by information on the amount of prescribed subcutaneous TNFi collected from pharmacies during each year, retrieved from the Swedish Prescribed Drug Register. RESULTS: Two thousand five hundred ninety patients started a first TNFi 2006-2015, and after 1 year, 74% remained on their first TNFi. However, after 5 years, this figure was only 46%, although at that time 63% were still on treatment with any biologic, while 30% had no anti-rheumatic treatment at all. After discontinuing the first TNFi, 46% switched directly to a second TNFi, but the drug retention for the second and third TNFi grew successively shorter compared to that for the first TNFi. In contrast, patients remaining on treatment with their first subcutaneous TNFi gradually reduced the dose, so that during the fifth year of treatment only 66% had collected ≥ 75% of the defined daily doses for that year. CONCLUSION: Less than half of patients with AS will remain on their first TNFi after 5 years, but most are still on a biologic. While patients remaining on treatment with their first TNFi appear to be able to reduce the dose over time, a large proportion cycle through several biologics, and 1/3 have no anti-rheumatic treatment after 5 years. This indicates the importance of thorough follow-up programs as well as a need for alternative therapeutic options.

Impact of extra-articular spondyloarthritis manifestations and comorbidities on drug retention of a first TNF-inhibitor in ankylosing spondylitis: a population-based nationwide study.

OBJECTIVES: To assess the impact of extra-articular spondyloarthritis (SpA) manifestations (anterior uveitis, psoriasis and inflammatory bowel disease (IBD)), and of comorbidities, on tumour necrosis factor alpha inhibitor (TNFi) drug retention in ankylosing spondylitis (AS). METHODS: We identified all bio-naïve patients with AS starting a first ever TNFi July 2006 to December 2015 from the Swedish Rheumatology Quality register and followed these from treatment start through December 2015. We determined the presence of extra-articular SpA-manifestations, comorbidities (cardiovascular disease, affective disease, diabetes, malignancies, chronic lung disease and kidney disease) and socioeconomic status before TNFi start, through linkage to five other national registers, and calculated, for each factor, crude and adjusted HRs for discontinuing the TNFi. RESULTS: 2577 patients with AS (71% men) started a first TNFi during the study period. 27% had a history of anterior uveitis, 6% psoriasis and 7% IBD. Anterior uveitis was associated with a superior TNFi drug retention (HR 0.72; 0.62 to 0.83), psoriasis with an inferior (HR 1.48; 1.18 to 1.86), whereas IBD did not affect TNFi drug retention. The effect of the SpA manifestations on TNFi drug retention was of a similar magnitude to that of the comorbidities. CONCLUSIONS: In AS, anterior uveitis and psoriasis, but not IBD, affect TNFi drug retention. Possible explanations include differential effects of TNFi on these extra-articular SpA manifestations, or inherent differences in AS, associated with the inflammatory phenotype. Further, comorbidities and socioeconomy affect TNFi drug retention to a similar magnitude as the SpA manifestations, and should, as such, receive due attention in clinical practice.

Genome-wide association study and gene expression analysis identifies CD84 as a predictor of response to etanercept therapy in rheumatoid arthritis.

Anti-tumor necrosis factor alpha (anti-TNF) biologic therapy is a widely used treatment for rheumatoid arthritis (RA). It is unknown why some RA patients fail to respond adequately to anti-TNF therapy, which limits the development of clinical biomarkers to predict response or new drugs to target refractory cases. To understand the biological basis of response to anti-TNF therapy, we conducted a genome-wide association study (GWAS) meta-analysis of more than 2 million common variants in 2,706 RA patients from 13 different collections. Patients were treated with one of three anti-TNF medications: etanercept (n = 733), infliximab (n = 894), or adalimumab (n = 1,071). We identified a SNP (rs6427528) at the 1q23 locus that was associated with change in disease activity score (ΔDAS) in the etanercept subset of patients (P = 8 × 10(-8)), but not in the infliximab or adalimumab subsets (P>0.05). The SNP is predicted to disrupt transcription factor binding site motifs in the 3' UTR of an immune-related gene, CD84, and the allele associated with better response to etanercept was associated with higher CD84 gene expression in peripheral blood mononuclear cells (P = 1 × 10(-11) in 228 non-RA patients and P = 0.004 in 132 RA patients). Consistent with the genetic findings, higher CD84 gene expression correlated with lower cross-sectional DAS (P = 0.02, n = 210) and showed a non-significant trend for better ΔDAS in a subset of RA patients with gene expression data (n = 31, etanercept-treated). A small, multi-ethnic replication showed a non-significant trend towards an association among etanercept-treated RA patients of Portuguese ancestry (n = 139, P = 0.4), but no association among patients of Japanese ancestry (n = 151, P = 0.8). Our study demonstrates that an allele associated with response to etanercept therapy is also associated with CD84 gene expression, and further that CD84 expression correlates with disease activity. These findings support a model in which CD84 genotypes and/or expression may serve as a useful biomarker for response to etanercept treatment in RA patients of European ancestry.

Genetic variation of ESR1 and its co-activator PPARGC1B is synergistic in augmenting the risk of estrogen receptor-positive breast cancer.

INTRODUCTION: Given the role of estrogen in breast carcinogenesis and the modification of estrogen receptor (ER) activity by its biochemical cofactors, we hypothesize that genetic variation within ER cofactor genes alters cellular response to estrogen exposure and consequently modifies the risk for ER-positive breast cancer. METHODS: We genotyped 790 tagging SNPs within 60 ER cofactor genes in 1,257 cases and 1,464 controls from Sweden and in 2,215 cases and 1,265 controls from Finland, and tested their associations with either ER-positive or ER-negative breast cancer. RESULTS: Seven SNPs showed consistent association with ER-positive breast cancer in the two independent samples, and six of them were located within PPARGC1B, encoding an ER co-activator, with the strongest association at rs741581 (odds ratio = 1.41, P = 4.84 × 10⁻5) that survived Bonferroni correction for multiple testing in the combined ER-positive breast cancer sample (Pcorrected = 0.03). Moreover, we also observed significant synergistic interaction (Pinteraction = 0.008) between the genetic polymorphisms within PPARGC1B and ESR1 in ER-positive breast cancer. By contrast, no consistent association was observed in ER-negative breast cancer. Furthermore, we found that administration of estrogen in the MCF-7 cell line induced PPARGC1B expression and enhanced occupancies of ER and RNA polymerase II within the region of SNP association, suggesting the upregulation of PPARGC1B expression by ESR1 activation. CONCLUSIONS: Our study revealed that DNA polymorphisms of PPARGC1B, coding a bona fide ER co-activator, are associated with ER-positive breast cancer risk. The feed-forward transcriptional regulatory loop between PPARGC1B and ESR1 further augments their protein interaction, which provides a plausible mechanistic explanation for the synergistic genetic interaction between PPARGC1B and ESR1 in ER-positive breast cancer. Our study also highlights that biochemically and genomically informed candidate gene studies can enhance the discovery of interactive disease susceptibility genes.

Patients with early rheumatoid arthritis who smoke are less likely to respond to treatment with methotrexate and tumor necrosis factor inhibitors: observations from the Epidemiological Investigation of Rheumatoid Arthritis and the Swedish Rheumatology Register cohorts.

OBJECTIVE: To determine whether cigarette smoking influences the response to treatment in patients with early rheumatoid arthritis (RA). METHODS: We retrieved clinical information about patients entering the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) early RA cohort from 1996 to 2006 (n=1,998) who were also in the Swedish Rheumatology Register (until 2007). Overall, 1,430 of the 1,621 registered patients were followed up from the time of inclusion in the EIRA cohort. Of these, 873 started methotrexate (MTX) monotherapy at inclusion, and 535 later started treatment with a tumor necrosis factor (TNF) inhibitor as the first biologic agent. The primary outcome was a good response according to the European League Against Rheumatism criteria at the 3-month visit. The influence of cigarette smoking (current or past) on the response to therapy was evaluated by logistic regression, with never smokers as the referent group. RESULTS: Compared with never smokers, current smokers were less likely to achieve a good response at 3 months following the start of MTX (27% versus 36%; P=0.05) and at 3 months following the start of TNF inhibitors (29% versus 43%; P=0.03). In multivariate analyses in which clinical, serologic, and genetic factors were considered, the inverse associations between current smoking and good response remained (adjusted odds ratio [OR] for MTX response 0.60 [95% CI 0.39-0.94]; adjusted OR for TNF inhibitor response 0.52 [95% CI 0.29-0.96]). The lower likelihood of a good response remained at later followup visits. Evaluating remission or joint counts yielded similar findings. Past smoking did not affect the chance of response to MTX or TNF inhibitors. Evaluating the overall cohort, which reflects all treatments used, current smoking was similarly associated with a lower chance of a good response (adjusted ORs for the 3-month, 6-month, 1-year, and 5-year visits 0.61, 0.65, 0.78, 0.66, and 0.61, respectively). CONCLUSION: Among patients with early RA, current cigarette smokers are less likely to respond to MTX and TNF inhibitors.

Genetic variation in the androgen estrogen conversion pathway in relation to breast cancer prognosticators.

Genetic variation in the androgen-to-estrogen conversion pathway has been shown to be associated with risk of breast cancer and, in particular, with estrogen receptor (ER) positive tumours. We aimed at studying how the genetic alterations, which have been identified for risk, are associated with breast cancer prognosticators, with a prior hypothesis that, in general, hormone-related breast cancers have a better prognosis than non-hormone-related breast cancers. Association between tagging SNPs in genes involved in estrogen metabolism and patient's lymph node status, tumour size and histological grade were estimated in a sample of 1569 Swedish breast cancer patients. Polymorphisms in CYP19A1, which have previously been linked to breast cancer risk, are shown to be associated with breast cancer prognosticators. The strongest association was observed for rs4646, with histological grade. The common allele of rs4646, which has been associated with increased breast cancer risk, was associated with low-histological grade and small tumour size (P = 0.001 and 0.015; 1-sided, respectively). We also found evidence that SNP rs7167936 is associated with histological grade and tumour size (P = 0.010 and 0.005; 1-sided, respectively). We show that rs4646 and rs7167936 are associated with histological grade even amongst only ER-positive tumours (P = 0.008 and 0.011; 1-sided, respectively). Our results provide new evidence that CYP19A1 is involved in both breast cancer risk and prognosis.

Multi-variant pathway association analysis reveals the importance of genetic determinants of estrogen metabolism in breast and endometrial cancer susceptibility.

Despite the central role of estrogen exposure in breast and endometrial cancer development and numerous studies of genes in the estrogen metabolic pathway, polymorphisms within the pathway have not been consistently associated with these cancers. We posit that this is due to the complexity of multiple weak genetic effects within the metabolic pathway that can only be effectively detected through multi-variant analysis. We conducted a comprehensive association analysis of the estrogen metabolic pathway by interrogating 239 tagSNPs within 35 genes of the pathway in three tumor samples. The discovery sample consisted of 1,596 breast cancer cases, 719 endometrial cancer cases, and 1,730 controls from Sweden; and the validation sample included 2,245 breast cancer cases and 1,287 controls from Finland. We performed admixture maximum likelihood (AML)-based global tests to evaluate the cumulative effect from multiple SNPs within the whole metabolic pathway and three sub-pathways for androgen synthesis, androgen-to-estrogen conversion, and estrogen removal. In the discovery sample, although no single polymorphism was significant after correction for multiple testing, the pathway-based AML global test suggested association with both breast (p(global) = 0.034) and endometrial (p(global) = 0.052) cancers. Further testing revealed the association to be focused on polymorphisms within the androgen-to-estrogen conversion sub-pathway, for both breast (p(global) = 0.008) and endometrial cancer (p(global) = 0.014). The sub-pathway association was validated in the Finnish sample of breast cancer (p(global) = 0.015). Further tumor subtype analysis demonstrated that the association of the androgen-to-estrogen conversion sub-pathway was confined to postmenopausal women with sporadic estrogen receptor positive tumors (p(global) = 0.0003). Gene-based AML analysis suggested CYP19A1 and UGT2B4 to be the major players within the sub-pathway. Our study indicates that the composite genetic determinants related to the androgen-estrogen conversion are important for the induction of two hormone-associated cancers, particularly for the hormone-driven breast tumour subtypes.

Rheumatoid arthritis risk allele PTPRC is also associated with response to anti-tumor necrosis factor alpha therapy.

OBJECTIVE: Anti-tumor necrosis factor alpha (anti-TNF) therapy is a mainstay of treatment in rheumatoid arthritis (RA). The aim of the present study was to test established RA genetic risk factors to determine whether the same alleles also influence the response to anti-TNF therapy. METHODS: A total of 1,283 RA patients receiving etanercept, infliximab, or adalimumab therapy were studied from among an international collaborative consortium of 9 different RA cohorts. The primary end point compared RA patients with a good treatment response according to the European League Against Rheumatism (EULAR) response criteria (n = 505) with RA patients considered to be nonresponders (n = 316). The secondary end point was the change from baseline in the level of disease activity according to the Disease Activity Score in 28 joints (triangle upDAS28). Clinical factors such as age, sex, and concomitant medications were tested as possible correlates of treatment response. Thirty-one single-nucleotide polymorphisms (SNPs) associated with the risk of RA were genotyped and tested for any association with treatment response, using univariate and multivariate logistic regression models. RESULTS: Of the 31 RA-associated risk alleles, a SNP at the PTPRC (also known as CD45) gene locus (rs10919563) was associated with the primary end point, a EULAR good response versus no response (odds ratio [OR] 0.55, P = 0.0001 in the multivariate model). Similar results were obtained using the secondary end point, the triangle upDAS28 (P = 0.0002). There was suggestive evidence of a stronger association in autoantibody-positive patients with RA (OR 0.55, 95% confidence interval [95% CI] 0.39-0.76) as compared with autoantibody-negative patients (OR 0.90, 95% CI 0.41-1.99). CONCLUSION: Statistically significant associations were observed between the response to anti-TNF therapy and an RA risk allele at the PTPRC gene locus. Additional studies will be required to replicate this finding in additional patient collections.

The influence of menopausal hormone therapy on tumour characteristics and survival in endometrial cancer patients.

INTRODUCTION: Menopausal hormone therapy (MHT) is a well-established factor in endometrial carcinogenesis, and therefore, could have prognostic implications. We investigated the effects of ever use of MHT on tumour grade and depth of myometrial invasion and 5-year relative survival in postmenopausal endometrial cancer patients. MATERIALS AND METHODS: We used a nationwide, population-based case-case design, of 683 Swedish women aged 50-74 years diagnosed with endometrial cancer during 1994 to 1995, followed up to 5 years after diagnosis. We applied polytomous multiple logistic regression to investigate the associations between the use of MHT and tumour grade, and myometrial invasion and Poisson regression for modelling 5-year excess mortality. RESULTS: Compared to never use, ever use of any MHT entailed lower risks of having moderately and poorly differentiated tumours. The lowest odds ratios for poorly differentiated tumours were seen for ever users of cyclically combined oestrogen-progestin [OR=0.23 (95% CI=0.07-0.73)]. Ever users of any form of MHT; particularly, medium potency MHT users, had significantly lower risks for tumours with deep myometrial invasion. Adjusted estimated relative excess hazard ratios revealed significantly improved survival for ever users of any form of MHT [RER=0.40 (95% CI=0.16-0.97)]; in particular ever users of any form of oestrogens [RER=0.38 (95% CI=0.15-0.99)]. CONCLUSION: Endometrial cancer patients who were ever users of MHT had more favourable tumour characteristics and better survival compared to never users of MHT. These findings support the notion that MHT induces endometrial cancer with less aggressive characteristics.

On the origins of complex immune-mediated disease: the example of rheumatoid arthritis.

This essay discusses strategies for understanding the origins and outcomes of complex chronic inflammatory diseases using genetic and environmental determinants as tools for new definitions of disease subsets. Rheumatoid arthritis has been chosen as the prototype to illustrate these general concepts. Through recent data on two different disease subsets, it has been possible to devise a new molecular model for disease development by incorporating multiple genes and environmental agents which generate immune reactions that may eventually cause disease. These kinds of studies, aiming to integrate genetic epidemiology and molecular immunology, require close proximity between institutions for molecular medicine, clinical departments able to provide follow-up, careful surveillance of large patient groups and collaboration with experts in epidemiology and biostatistics.

Breast cancer incidence after hormonal infertility treatment in Sweden: a cohort study.

OBJECTIVE: To assess the impact of infertility treatment with causes of infertility on incidence of breast cancer. STUDY DESIGN: Historical prospective cohort study of 1135 women attending major university clinics for treatment of infertility in Sweden, 1961-1976. Women were classified as users of clomiphene citrate or gonadotropins, or a combination of both therapies. Standardized incidence ratios were calculated to estimate relative risk of breast cancer. RESULTS: We observed 54 cases of breast cancer during 1961-2004, which did not significantly exceed those expected. Users of high-dose clomiphene citrate had an almost 2-fold increased risk (standardized incidence ratio, 1.90; 95% confidence interval, 1.08-3.35). This association was more pronounced among women referred for nonovulatory factors, with 3-fold increased risk (standardized incidence ratio, 3.00; 95% confidence interval, 1.35-6.67). CONCLUSION: No overall increased risk for breast cancer was shown with infertility treatment. Women with nonovulatory causes treated with high-dose clomiphene citrate therapy may have an elevated risk for breast cancer.

Estrogen receptor alpha gene polymorphism and endometrial cancer risk--a case-control study.

BACKGROUND: Estrogen is an established endometrial carcinogen. One of the most important mediators of estrogenic action is the estrogen receptor alpha. We have investigated whether polymorphic variation in the estrogen receptor alpha gene (ESR1) is associated with endometrial cancer risk. METHODS: In 702 cases with invasive endometrial cancer and 1563 controls, we genotyped five markers in ESR1 and used logistic regression models to estimate odds ratios (OR) and 95 percent confidence intervals (CI). RESULTS: We found an association between rs2234670, rs2234693, as well as rs9340799, markers in strong linkage disequilibrium (LD), and endometrial cancer risk. The association with rs9340799 was the strongest, OR 0.75 (CI 0.60-0.93) for heterozygous and OR 0.53 (CI 0.37-0.77) for homozygous rare compared to those homozygous for the most common allele. Haplotype models did not fit better to the data than single marker models. CONCLUSION: We found that intronic variation in ESR1 was associated with endometrial cancer risk.

Menopausal hormone therapy in relation to breast cancer characteristics and prognosis: a cohort study.

INTRODUCTION: Menopausal hormone therapy has been reported to increase the risk of certain subtypes of breast cancer and to be associated with a favorable survival. These associations could either be due to an increased mammographic surveillance or to a biological effect. We assessed these associations in a Swedish cohort of postmenopausal breast cancer patients holding information on mammographic examinations, menopausal hormone therapy use, other breast cancer risk factors, and cancer treatment. METHODS: We analyzed 2,660 postmenopausal women aged 50 to 74 years, diagnosed with invasive breast cancer in 1993 to 1995 and followed until the end of 2003 (median follow-up, 9 years and 3 months). We assessed the influence of hormone therapy before diagnosis on tumor characteristics and breast cancer-specific survival. We analyzed hormone therapy before diagnosis by regimen (estrogen-progestin therapy or estrogen alone therapy), recency (current or past), and duration of use (<5 years or > or = 5 years). RESULTS: Current use, but not past use, compared with never use of hormone therapy before diagnosis seemed to be associated with tumors of low grade and with improved breast cancer-specific survival. The associations were stronger with longer duration, but did not vary significantly by regimen. The favorable survival among current users of hormone therapy was only partly explained by differences in available tumor characteristics and mammographic surveillance. CONCLUSIONS: We conclude that current menopausal hormone therapy, especially long term, is associated with favorable tumor characteristics and survival.

ESR1 and EGF genetic variation in relation to breast cancer risk and survival.

INTRODUCTION: Oestrogen exposure is a central factor in the development of breast cancer. Oestrogen receptor alpha (ESR1) is the main mediator of oestrogen effect in breast epithelia and has also been shown to be activated by epidermal growth factor (EGF). We sought to determine if common genetic variation in the ESR1 and EGF genes affects breast cancer risk, tumour characteristics or breast cancer survival. METHODS: We genotyped 157 single nucleotide polymorphisms (SNPs) in ESR1 and 54 SNPs in EGF in 92 Swedish controls and selected haplotype tagging SNPs (tagSNPs) that could predict both single SNP and haplotype variation in the genes with an R2 of at least 0.8. The tagSNPs were genotyped in 1,590 breast cancer cases and 1,518 controls, and their association with breast cancer risk, tumour characteristics and survival were assessed using unconditional logistic regression models, Cox proportional hazard models and haplotype analysis. RESULTS: The single tagSNP analysis did not reveal association evidence for breast cancer risk, tumour characteristics, or survival. A multi-locus analysis of five adjacent tagSNPs suggested a region in ESR1 (between rs3003925 and rs2144025) for association with breast cancer risk (p = 0.001), but the result did not withstand adjustment for multiple comparisons (p = 0.086). A similar region was also implicated by haplotype analyses, but its significance needs to be verified by follow-up analysis. CONCLUSION: Our results do not support a strong association between common variants in the ESR1 and EGF genes and breast cancer risk, tumour characteristics or survival.

Associations between androgen and Vitamin D receptor microsatellites and postmenopausal breast cancer.

We investigated the association between polymorphism in the androgen receptor (AR) and vitamin D receptor (VDR) genes and breast cancer risk in a large population-based case-control study of genetically homogenous Swedish women. We successfully determined both AR CAG(n) and VDR A(n) genotype in 1,502 women with invasive breast cancer and in 1,510 control women. We did not find any associations between AR or VDR microsatellite lengths and breast cancer when we used a priori determined cutoffs (/=22 repeats for AR and /=19 for VDR) to define long and short alleles. There was statistically significant interaction between VDR genotype and parity, such that women with two short alleles had a halved risk for breast cancer, irrespective of parity, compared with nulliparous women with two long alleles. Homozygosity for the long VDR allele was associated with a more advanced clinical stage at diagnosis. In exploratory analyses, we determined cutoffs based on visual inspection of distributions of allele lengths among cases and controls and found that women carrying two alleles with <20 AR CAG(n) repeats had an increased risk for breast cancer, odds ratio of 1.67 (95% confidence interval, 1.17-2.38), compared with those with two alleles with >/=20 repeats. Women carrying two VDR alleles with <21 A(n) were also at an increased risk, odds ratio of 1.26 (95% confidence interval, 1.04-1.51). Our data do not support major roles for AR or VDR polymorphism as breast cancer risk factors. However, we did find an interaction between VDR genotype and parity that remains to be corroborated.

Meta- and pooled analyses of the cytochrome P-450 1B1 Val432Leu polymorphism and breast cancer: a HuGE-GSEC review.

The association between the cytochrome P-450 1B1 (CYP1B1) Val432Leu polymorphism and breast cancer was assessed through a meta-analysis of all published case-control studies and a pooled analysis of both published and unpublished case-control studies from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database ( www.upci.upmc.edu/research/ccps/ccontrol/g_intro.html ). GSEC is a collaborative project that gathers information on studies of metabolic gene polymorphisms and cancer. Thirteen articles were included in the meta-analysis (14,331 subjects; 7,514 cases, 6,817 controls); nine data sets were included in the pooled analysis (6,842 subjects; 3,391 cases, 3,451 controls). A summary meta- or pooled estimate of the association between the CYP1B1 Val432Leu polymorphism and breast cancer could not be calculated because of statistically significant heterogeneity in the point estimates among studies. No association between the CYP1B1 Val432Leu polymorphism and breast cancer was observed in Asians (for Val/Val and Val/Leu combined, odds ratio (OR) = 1.0, 95% confidence interval (CI): 0.8, 1.2). An inverse association was observed in populations of mixed/African origin (OR = 0.8, 95% CI: 0.7, 0.9). The pooled analysis suggested a possible association in Caucasians (for Val/Val and Val/Leu combined, OR = 1.5, 95% CI: 1.1, 2.1), with effect modification across age categories. The observed effect of age on the association in Caucasians indicates that further studies are needed on the role of CYP1B1 Val432Leu in estrogen metabolism according to age, ethnicity, and menopausal status.