Driving restrictions for Dutch patients with an implantable cardioverter defibrillator : Compliance and associated factors.

BACKGROUND: Dutch patients with an implantable cardioverter defibrillator (ICD) are restricted from driving for two months after implantation or shocks. This requires significant lifestyle adjustments and is one of the primary concerns of ICD patients. Previous studies indicated that compliance with the driving restrictions is poor, but insight in socio-demographic, clinical and psychological factors associated with compliance is limited. Hence, this study aimed to explore compliance with the driving restrictions and associated factors in a large sample of Dutch ICD patients. METHOD: Dutch ICD patients (N = 313) completed an elaborative set of questionnaires at time of implantation and at four months after implantation, assessing socio-demographic, psychological and driving-related characteristics. Clinical data were collected from the patients' medical records. RESULTS: A substantial subgroup (28%) of the patient sample (median age 64 (interquartile range = 55-71), 81% male) reported to have been noncompliant with the driving restrictions. Univariate analysis indicated that noncompliant patients more often considered refusing the ICD due to the restrictions, compared to compliant patients (19% versus 10%, p = 0.02). Multivariate analysis showed that the feeling of understanding the reason behind the driving restrictions was associated with better compliance (odds ratio = 2.16, 95% confidence interval 1.02-4.56, p = 0.04). No other socio-demographic, clinical, psychological or driving-related factors were associated with compliance. CONCLUSION: A large number of ICD patients does not comply with the driving restrictions after implantation. This study emphasised the importance of the patient's feeling of understanding the reason behind the restrictions.

Patient-reported health status prior to cardiac resynchronisation therapy identifies patients at risk for poor survival and prolonged hospital stays.

BACKGROUND: Patient-reported factors have largely been neglected in search of predictors of response to cardiac resynchronisation therapy (CRT). The current study aimed to examine the independent value of pre-implantation patient-reported health status in predicting four-year survival and cardiac-related hospitalisation of CRT patients. METHODS: Consecutive patients (N = 139) indicated to receive a first-time CRT-defibrillator at the University Medical Center Utrecht were asked to complete a set of questionnaires prior to implantation. The Kansas City Cardiomyopathy Questionnaire (KCCQ) was used to assess heart failure-specific health status. Data on patients' demographic, clinical and psychological characteristics at baseline, and on cardiac-related hospitalisations and all-cause deaths during a median follow-up of 3.9 years were obtained from purpose-designed questionnaires and patients' medical records. RESULTS: Results of multivariable Cox regression analyses showed that poor patient-reported health status (KCCQ score < 50) prior to implantation was associated with a 2.5-fold increased risk of cardiac hospitalisation or all-cause death, independent of sociodemographic, clinical and psychological risk factors (adjusted hazard ratio 2.46, 95 % confidence interval (CI) 1.30-4.65). Poor health status was not significantly associated with the absolute number of cardiac-related hospital admissions, but with the total number of days spent in hospital during follow-up (adjusted incidence rate ratio 3.20, 95 % CI 1.88-5.44). CONCLUSIONS: Patient-reported health status assessed prior to CRT identifies patients at risk for poor survival and prolonged hospital stays, independent of traditional risk factors. These results emphasise the importance of incorporating health status measures in cardiovascular research and patient management. Heart failure patients reporting poor health status should be identified and offered appropriate additional treatment programs.

State of the art of ICD programming: Lessons learned and future directions.

The lifesaving benefits of implantable cardioverter defibrillator (ICD) therapy are more and more weighted against possible harm (e.g. unnecessary device therapy, procedural complications, device malfunction etc.) which might have adverse effects on patients' perceived health status and quality of life. Hence, there has been an increasing interest in the optimisation of ICD programming to prevent inappropriate and appropriate but unnecessary device therapy. The purpose of the current report is to give an overview of research into the optimisation of ICD programming and present the design of the on-going ENHANCED-ICD study. The ENHANCED-ICD study is a prospective, safety monitoring study enrolling 60 primary and secondary prophylactic ICD patients at the University Medical Center Utrecht. Patients implanted with any type of ICD with SmartShock technology(TM), and between 18-80 years of age, were eligible to participate. In all patients a prolonged detection of 60/80 intervals was programmed. The primary objective of the study is to investigate whether enhanced programming to further reduce ICD therapies is safe. The secondary objective is to examine the impact of enhanced programming on (i) antitachycardia pacing and shocks (both appropriate and inappropriate) and (ii) quality of life and distress. The first results of the ENHANCED-ICD study are expected in 2015.

Patient perspective on remote monitoring of cardiovascular implantable electronic devices: rationale and design of the REMOTE-CIED study.

BACKGROUND: Remote patient monitoring is a safe and effective alternative for the in-clinic follow-up of patients with cardiovascular implantable electronic devices (CIEDs). However, evidence on the patient perspective on remote monitoring is scarce and inconsistent. OBJECTIVES: The primary objective of the REMOTE-CIED study is to evaluate the influence of remote patient monitoring versus in-clinic follow-up on patient-reported outcomes. Secondary objectives are to: 1) identify subgroups of patients who may not be satisfied with remote monitoring; and 2) investigate the cost-effectiveness of remote monitoring. METHODS: The REMOTE-CIED study is an international randomised controlled study that will include 900 consecutive heart failure patients implanted with an implantable cardioverter defibrillator (ICD) compatible with the Boston Scientific LATITUDE® Remote Patient Management system at participating centres in five European countries. Patients will be randomised to remote monitoring or in-clinic follow-up. The In-Clinic group will visit the outpatient clinic every 3-6 months, according to standard practice. The Remote Monitoring group only visits the outpatient clinic at 12 and 24 months post-implantation, other check-ups are performed remotely. Patients are asked to complete questionnaires at five time points during the 2-year follow-up. CONCLUSION: The REMOTE-CIED study will provide insight into the patient perspective on remote monitoring in ICD patients, which could help to support patient-centred care in the future.

Venous and arterial thromboembolism after colorectal cancer in the Netherlands: Incidence, predictors, and prognosis.

BACKGROUND: Colorectal cancer (CRC) is the third most prevalent cancer type. CRC-patients are at increased risk of venous and arterial thromboembolism (TE), but the magnitude of the risks, their predictors and consequences are not exactly known. OBJECTIVES: We aimed to determine incidence, predictors and prognosis of TE after incident CRC in a large, unselected population. METHODS: Using data from Statistics Netherlands and the Netherlands Comprehensive Cancer Organization, all incident CRC-patients were identified between 2013 and 2018 plus a sample of 1:2 age- and sex-matched control subjects. Incidence rates and cumulative incidences for TE were estimated. Predictor variables for TE were explored by univariable Cox regression. The association between TE and all-cause mortality was evaluated by multivariable time-dependent Cox regression. RESULTS: 68,238 incident CRC-patients were matched to 136,476 controls. CRC-patients had a 1-year cumulative venous TE (VTE) incidence of 1.93 % (95%CI 1.83-2.04), versus 0.24 % (95%CI 0.21-0.27) in controls (HR 8.85; 95%CI 7.83-9.99). For arterial TE (ATE), this was 2.74 % (95%CI 2.62-2.87) in CRC versus 1.88 % (95%CI 1.81-1.95) in controls (HR 1.57; 95%CI 1.47-1.66). Cancer stage, surgery, chemotherapy and asthma were predictors for VTE, whereas age, prior ATE and Parkinson's disease were predictors for ATE. CRC patients with TE had an increased risk of all-cause mortality (VTE HR; 3.68 (95%CI 3.30-4.10, ATE HR; 3.05 (95%CI 2.75-3.39)) compared with CRC-patients without TE. CONCLUSIONS: This Dutch nationwide cohort study adds detailed knowledge on the risk of VTE and ATE, their predictors and prognosis in CRC-patients. These findings may drive TE prophylactic management decisions.

Assessment of breast cancer progression and metastasis during a hypercoagulable state induced by silencing of antithrombin in a xenograft mouse model.

Local coagulation activation has been shown to impact both primary tumor growth and metastasis in mice. It is well known that components of the blood clotting cascade such as tissue factor and thrombin play a role in tumor progression by activating cellular receptors and local formation of fibrin. However, whether venous thromboembolism (VTE) or a hypercoagulable state has a direct impact on cancer progression is unknown. Here we have combined an orthotopic murine breast cancer model, using female Nod-SCID mice, with siRNA-mediated silencing of antithrombin (siAT) leading to the induction of a systemic hypercoagulable state. We show that, compared to control siRNA-treated (not experiencing a hypercoagulable state) tumor-bearing mice, siAT treated tumor-bearing mice do not show enhanced tumor growth nor enhanced metastasis. We conclude that, in this murine model for hypercoagulability, induction of a hypercoagulable state does not contribute to breast cancer progression.

Alternatively spliced tissue factor induces angiogenesis through integrin ligation.

The initiator of coagulation, full-length tissue factor (flTF), in complex with factor VIIa, influences angiogenesis through PAR-2. Recently, an alternatively spliced variant of TF (asTF) was discovered, in which part of the TF extracellular domain, the transmembrane, and cytoplasmic domains are replaced by a unique C terminus. Subcutaneous tumors produced by asTF-secreting cells revealed increased angiogenesis, but it remained unclear if and how angiogenesis is regulated by asTF. Here, we show that asTF enhances angiogenesis in matrigel plugs in mice, whereas a soluble form of flTF only modestly enhances angiogenesis. asTF dose-dependently upregulates angiogenesis ex vivo independent of either PAR-2 or VIIa. Rather, asTF was found to ligate integrins, resulting in downstream signaling. asTF-alphaVbeta3 integrin interaction induces endothelial cell migration, whereas asTF-dependent formation of capillaries in vitro is dependent on alpha6beta1 integrin. Finally, asTF-dependent aortic sprouting is sensitive to beta1 and beta3 integrin blockade and a TF-antibody that disrupts asTF-integrin interaction. We conclude that asTF, unlike flTF, does not affect angiogenesis via PAR-dependent pathways but relies on integrin ligation. These findings indicate that asTF may serve as a target to prevent pathological angiogenesis.

A validated model of GAG deposition, cell distribution, and growth of tissue engineered cartilage cultured in a rotating bioreactor.

In this work a new phenomenological model of growth of cartilage tissue cultured in a rotating bioreactor is developed. It represents an advancement of a previously derived model of deposition of glycosaminoglycan (GAG) in engineered cartilage by (i) introduction of physiological mechanisms of proteoglycan accumulation in the extracellular matrix (ECM) as well as by correlating (ii) local cell densities and (iii) tissue growth to the ECM composition. In particular, previously established predictions and correlations of local oxygen concentrations and GAG synthesis rates are extended to distinguish cell secreted proteoglycan monomers free to diffuse in cell surroundings and outside from the engineered construct, from large aggrecan molecules, which are constrained within the ECM and practically immovable. The model includes kinetics of aggregation, that is, transformation of mobile GAG species into immobile aggregates as well as maintenance of the normal ECM composition after the physiological GAG concentration is reached by incorporation of a product inhibition term. The model also includes mechanisms of the temporal evolution of cell density distributions and tissue growth under in vitro conditions. After a short initial proliferation phase the total cell number in the construct remains constant, but the local cell distribution is leveled out by GAG accumulation and repulsion due to negative molecular charges. Furthermore, strong repulsive forces result in expansion of the local tissue elements observed macroscopically as tissue growth (i.e., construct enlargement). The model is validated by comparison with experimental data of (i) GAG distribution and leakage, (ii) spatial-temporal distributions of cells, and (iii) tissue growth reported in previous works. Validation of the model predictive capability--against a selection of measured data that were not used to construct the model--suggests that the model successfully describes the interplay of several simultaneous processes carried out during in vitro cartilage tissue regeneration and indicates that this approach could also be attractive for application in other tissue engineering systems.

Alternatively spliced tissue factor. A crippled protein in coagulation or a key player in non-haemostatic processes?

Full-length tissue factor (flTF) initiates coagulation, but also exerts non-hemostatic functions such as inflammation and angiogenesis through protease activated receptors (PARs). In 2003 a soluble variant of flTF was described which results from alternative splicing. Since its discovery the role of alternatively spliced tissue factor (asTF) in coagulation has been debated. asTF may have pro-coagulant properties but due to structural differences when compared to flTF, asTF coagulant function may be relatively low. Nevertheless, similar to flTF, asTF appears to have non-hemostatic properties; asTF expression in tumors correlates with increased tumor size, vessel number and poor survival in some cancer types, and drives tumor growth in animal models. Interestingly, unlike flTF, asTF does not promote angiogenesis through activating PARs but rather via integrin ligation. flTF is a critical determinant in cardiovascular disease but little is known about asTF in cardiovascular disease. asTF is produced by monocytes and macrophages, thus macrophage-derived asTF may contribute to atherosclerotic disease. In conclusion, unraveling asTF's non-hemostatic properties may generate new insights in the pathophysiology and diagnostics of cancer and cardiovascular disease.

[Myocarditis, a treacherous condition]. / Myocarditis, een verraderlijk ziektebeeld.

Myocarditis, a treacherous condition It is important to recognize myocarditis at an early stage. To illustrate this, we present two male patients aged 39 and 51, respectively, who were admitted with febrile disease and signs of circulatory instability. Initially, myocarditis was not suspected in these patients. After the sudden death of the younger patient it was discovered that he had had fulminant myocarditis. Its nonspecific, heterogeneous clinical presentation, and potentially disastrous outcome make myocarditis a treacherous condition, which mainly affects younger adults. Although its aetiology is broad, the primary cause in the western world is a viral infection leading to lymphocytic myocarditis. Fulminant forms are rare, but this diagnosis needs to be considered in patients with an atypical illness and impaired haemodynamics or electrocardiogram (ECG) abnormalities. Early and liberal consultation of a cardiologist is important. Primary diagnostics include blood testing (e.g. troponin, creatinine kinase), ECG, echocardiography and exclusion of coronary ischaemia. The diagnosis can be confirmed by cardiovascular MRI or endomyocardial biopsy.

mTOR kinase inhibition reduces tissue factor expression and growth of pancreatic neuroendocrine tumors.

Essentials Tissue factor (TF) isoforms are expressed in pancreatic neuroendocrine tumors (pNET). TF knockdown inhibits proliferation of human pNET cells in vitro. mTOR kinase inhibitor sapanisertib/MLN0128 suppresses TF expression in human pNET cells. Sapanisertib suppresses TF expression and activity and reduces the growth of pNET tumors in vivo. SUMMARY: Background Full-length tissue factor (flTF) and alternatively spliced TF (asTF) contribute to growth and spread of pancreatic ductal adenocarcinoma. It is unknown, however, if flTF and/or asTF contribute to the pathobiology of pancreatic neuroendocrine tumors (pNETs). Objective To assess TF expression in pNETs and the effects of mTOR complex 1/2 (mTORC1/2) inhibition on pNET growth. Methods Human pNET specimens were immunostained for TF. Human pNET cell lines QGP1 and BON were evaluated for TF expression and responsiveness to mTOR inhibition. shRNA were used to knock down TF in BON. TF cofactor activity was assessed using a two-step FXa generation assay. TF promoter activity was assessed using transient transfection of human TF promoter-driven reporter constructs into cells. Mice bearing orthotopic BON tumors were treated with the mTORC1/2 ATP site competitive inhibitor sapanisertib/MLN0128 (3 mg kg-1 , oral gavage) for 34 days. Results Immunostaining of pNET tissue revealed flTF and asTF expression. BON and QGP1 expressed both TF isoforms, with BON exhibiting higher levels. shRNA directed against TF suppressed BON proliferation in vitro. Treatment of BON with sapanisertib inhibited mTOR signaling and suppressed TF levels. BON tumors grown in mice treated with sapanisertib had significantly less TF protein and cofactor activity, and were smaller compared with tumors grown in control mice. Conclusions TF isoforms are expressed in pNETs. Sapanisertib suppresses TF mRNA and protein expression as well as TF cofactor activity in vitro and in vivo. Thus, further studies are warranted to evaluate the clinical utility of TF-suppressing mTORC1/2 inhibitor sapanisertib in pNET management.

Optical diagnostics studies of air flow and powder fluidisation in Nexthaler®. Part II: Use of fluorescent imaging to characterise transient release of fines from a dry powder inhaler.

The fine particle fraction is a key indicator of therapeutic effectiveness of inhaled pharmaceutical aerosols. This paper presents a fluorescence imaging technique to visualise and characterise the emission of active pharmaceutical ingredient (API) fines in model formulations containing coarse lactose carrier and 1.5-2 µm diameter fluorescent microspheres (model API fines). A two-camera arrangement was used to acquire simultaneous images of spatial and temporal distribution of model API fines and fluidised powder formulation near the mouthpiece exit of a DPI. Digital image analysis showed that the model API fines were released along with the bulk of the powder dose. More rapidly accelerating airflows were found to cause earlier release of API fines. The fluorescence imaging technique analyses a substantial fraction of the aerosol plume and was found to provide effective time-resolved characterisation of the de-aggregation and release of API fines with consistent results across a wide range of model API concentrations. Future studies should demonstrate the usefulness of the fluorescence imaging technique across different formulations and DPI devices.

Genes associated with venous thromboembolism in colorectal cancer patients.

Essentials The underlying pathophysiological mechanisms behind cancer-associated thrombosis are unknown. We compared expression profiles in tumor cells from patients with and without thrombosis. Tumors from patients with thrombosis showed significant differential gene expression profiles. Patients with thrombosis had a proinflammatory status and increased fibrin levels in the tumor. SUMMARY: Background Venous thromboembolism (VTE) is a frequent complication in patients with cancer, and is associated with significant morbidity and mortality. However, the mechanisms behind cancer-associated thrombosis are still incompletely understood. Objectives To identify novel genes that are associated with VTE in patients with colorectal cancer (CRC). Methods Twelve CRC patients with VTE were age-matched and sex-matched to 12 CRC patients without VTE. Tumor cells were isolated from surgical samples with laser capture microdissection approaches, and mRNA profiles were measured with next-generation RNA sequencing. Results This approach led to the identification of new genes and pathways that might contribute to VTE in CRC patients. Application of ingenuity pathway analysis indicated significant links with inflammation, the methionine degradation pathway, and increased platelet function, which are all key processes in thrombus formation. Tumor samples of patients with VTE had a proinflammatory status and contained higher levels of fibrin and fibrin degradation products than samples of those without VTE. Conclusion This case-control study provides a proof-of-principle that tumor gene expression can discriminate between cancer patients with low and high risks of VTE. These findings may help to further unravel the pathogenesis of cancer-related VTE. The identified genes could potentially be used as candidate biomarkers to select high-risk CRC patients for thromboprophylaxis.

Interplay between alternatively spliced Tissue Factor and full length Tissue Factor in modulating coagulant activity of endothelial cells.

BACKGROUND: Full length Tissue factor (flTF) is a key player in hemostasis and also likely contributes to venous thromboembolism (VTE), the third most common cardiovascular disease. flTF and its minimally coagulant isoform, alternatively spliced TF (asTF), have been detected in thrombi, suggesting participation of both isoforms in thrombogenesis, but data on participation of asTF in hemostasis is lacking. Therefore, we assessed the role of asTF in flTF cofactor activity modulation, using a co-expression system. OBJECTIVE: To investigate the interplay between flTF and asTF in hemostasis on endothelial cell surface. METHODS: Immortalized endothelial (ECRF) cells were adenovirally transduced to express asTF and flTF, after which flTF cofactor activity was measured on cells and microvesicles (MVs). To study co-localization of flTF/asTF proteins, confocal microscopy was performed. Finally, intracellular distribution of flTF was studied in the presence or absence of heightened asTF levels. RESULTS: Levels of flTF antigen and cofactor activity were not affected by asTF co-expression. asTF and flTF were found to localize in distinct subcellular compartments. Only upon heightened overexpression of asTF, lower flTF protein levels and cofactor activity were observed. Heightened asTF levels also induced a shift of flTF from non-raft to lipid raft plasma membrane fractions, and triggered the expression of ER stress marker BiP. Proteasome inhibition resulted in increased asTF - but not flTF - protein expression. CONCLUSION: At moderate levels, asTF appears to have negligible impact on flTF cofactor activity on endothelial cells and MVs; however, at supra-physiological levels, asTF is able to reduce the levels of flTF protein and cofactor activity.

Illness perceptions in patients with heart failure and an implantable cardioverter defibrillator: Dimensional structure, validity, and correlates of the brief illness perception questionnaire in Dutch, French and German patients.

BACKGROUND: Patients' illness perceptions are associated with psychological wellbeing and can be measured with the Brief Illness Perception Questionnaire (B-IPQ). However, little is known about illness perceptions in patients with heart failure. We examined the dimensional structure, validity and clinical and psychological correlates of the B-IPQ in Dutch, French and German patients with heart failure and an implantable cardioverter defibrillator (ICD). METHOD: European heart failure patients (n=585) participating in the REMOTE-CIED study completed a set of questionnaires 1-2weeks post ICD-implantation, including the B-IPQ. Information on clinical data was captured from patients' medical records. RESULTS: A two-factor structure (I='Consequences'; II='Control') represented 7 out of 8 B-IPQ items in the total sample and Dutch, German and French subgroups. The total B-IPQ had a Cronbach's α of 0.69, with the 'Consequences' subscale being more internally consistent (α=0.80). Both the B-IPQ and its 'Consequences' subscale were significantly correlated with a number of psychological characteristics, but not with clinical characteristics. Multivariable logistic regression analysis indicated that threatening illness perceptions as measured with the total B-IPQ were associated with poor health status (OR=2.66, 95%CI=1.72-4.11), anxiety (OR=1.79, 95%CI=1.001-3.19), depression (OR=2.81, 95%CI=1.65-4.77), negative affectivity (OR=1.93, 95%CI=1.21-3.09) and poor ICD acceptance (OR=2.68, 95%CI=1.70-4.22). CONCLUSION: The B-IPQ demonstrated good psychometric properties in Dutch, French and German patients with heart failure. Psychological factors were the most important correlates of patients' perceptions of heart failure, emphasizing the importance of targeting maladaptive illness perceptions in this population, due to their impact on patients' wellbeing and quality of life.

Cell biology of tissue factor, an unusual member of the cytokine receptor family.

Tissue factor (TF) is a 47-kDa transmembrane protein, involved in the onset of coagulation. However, it also influences pathophysiological processes such as inflammation and tumor angiogenesis. Although the molecular mechanisms responsible for these phenomena remain unclear, it is thought that they are brought about by the action of intracellular signaling, resulting in gene transcription and subsequent protein synthesis. In this review we focus on FVIIa/TF-induced intracellular signaling and its possible role in physiology.

Optical diagnostics study of air flow and powder fluidisation in Nexthaler®--Part I: Studies with lactose placebo formulation.

Effective drug delivery to the lungs by a DPI device requires the air-stream through the device to have sufficient power to aerosolise the powder. Furthermore, sufficient turbulence must be induced, along with particle-wall and particle-particle collisions, in order to de-aggregate small drug particles from large carrier particles. As a result, the emitted and the fine particle doses produced by many commercially available DPI devices tend to be strongly affected by the natural inter-patient variability of the inhaled air flow. The Nexthaler® is a multi-dose breath-actuated dry-powder inhaler with minimum drug delivery-flow rate dependency and incorporating a dose protector. The actuation mechanism of the dose-protector ensures that the dose is only exposed to the inhaled air flow if the flow has sufficient power to cause complete aerosolisation. For this study, a proprietary lactose placebo powder blend was filled into "transparent" Nexthaler® to allow application of high-speed imaging and particle image velocimetry (PIV) techniques to successfully interrogate and reveal details of the powder entrainment and emission processes coupled with characterisation of the flow environment in the vicinity of the mouthpiece exit. The study showed that fluidisation of the bulk of the powder occurs very quickly (∼20ms) after withdrawal of the dose protector followed by powder emission from the device within ∼50ms thereafter. The bulk of the metered placebo dose was emitted within 100-200ms. The visualisation study also revealed that a very small fraction of powder fines is emitted whilst the dose protector still covers the dosing cup as the flow rate through the device accelerates. The PIV results show that the flow exiting the device is highly turbulent with a rotating flow structure, which forces the particles to follow internal paths having a high probability of wall impacts, suggesting that the flow environment inside the Nexthaler® DPI will be very beneficial for carrier-drug de-aggregation.

Alternatively spliced tissue factor synergizes with the estrogen receptor pathway in promoting breast cancer progression.

BACKGROUND: Procoagulant full-length tissue factor (flTF) and its minimally coagulant alternatively spliced isoform (asTF), promote breast cancer (BrCa) progression via different mechanisms. We previously showed that flTF and asTF are expressed by BrCa cells, resulting in autoregulation in a cancer milieu. BrCa cells often express hormone receptors such as the estrogen receptor (ER), leading to the formation of hormone-regulated cell populations. OBJECTIVE: To investigate whether TF isoform-specific and ER-dependent pathways interact in BrCa. METHODS: Tissue factor isoform-regulated gene sets were assessed using ingenuity pathway analysis. Tissues from a cohort of BrCa patients were divided into ER-positive and ER-negative groups. Associations between TF isoform levels and tumor characteristics were analyzed in these groups. BrCa cells expressing TF isoforms were assessed for proliferation, migration and in vivo growth in the presence or absence of estradiol. RESULTS: Ingenuity pathway analysis pointed to similarities between ER- and TF-induced gene expression profiles. In BrCa tissue specimens, asTF expression was associated with grade and stage in ER-positive but not in ER-negative tumors. flTF was only associated with grade in ER-positive tumors. In MCF-7 cells, asTF accelerated proliferation in the presence of estradiol in a ß1 integrin-dependent manner. No synergy between asTF and the ER pathway was observed in a migration assay. Estradiol accelerated the growth of asTF-expressing tumors but not control tumors in vivo in an orthotopic setting. CONCLUSION: Tissue factor isoform and estrogen signaling share downstream targets in BrCa; the concomitant presence of asTF and estrogen signaling is required to promote BrCa cell proliferation.