The role of the pathologist in the design and conducting of biomarker-driven clinical trials in cancer: position paper of the European Society of Pathology.

Clinical trials in oncology are important tools to identify and establish new effective drugs for cancer treatment. Since the development of the concept of precision oncology, a huge number of multi-centric biomarker-driven clinical trials have been performed and promoted by either academic institutions or pharmaceutical companies. In this scenario, the role of pathologists is essential in multiple aspects, with new challenges that should be addressed.

Standardization through education of molecular pathology: a spotlight on the European Masters in Molecular Pathology.

Despite advancements in precision medicine, many cancer patients globally, particularly those in resource-constrained environments, face significant challenges in accessing high-quality molecular testing and targeted therapies. The considerable heterogeneity in molecular testing highlights the urgent need to harmonize practices across Europe and beyond, establishing a more standardized and consistent approach in MP laboratories. Professionals, especially molecular pathologists, must move beyond traditional education to cope with this heterogeneity.

Access and quality of biomarker testing for precision oncology in Europe.

Background: Predictive biomarkers are essential for selecting the best therapeutic strategy in patients with cancer. The International Quality Network for Pathology, the European Cancer Patient Coalition and the European Federation of Pharmaceuticals Industries and Associations evaluated the access to and quality of biomarker testing across Europe.

Methods: Data sources included surveys of 141 laboratory managers and 1.

Tumor mutation burden testing: a survey of the International Quality Network for Pathology (IQN Path).

While tumour mutation burden (TMB) is emerging as a possible biomarker for immune-checkpoint inhibitors (ICI), methods for testing have not been standardised as yet. In April 2019, the International Quality Network for Pathology (IQN Path) launched a survey to assess the current practice of TMB testing. Of the 127 laboratories that replied, 69 (54.

e-Learning for Instruction and to Improve Reproducibility of Scoring Tumor-Stroma Ratio in Colon Carcinoma: Performance and Reproducibility Assessment in the UNITED Study.

Background: The amount of stroma in the primary tumor is an important prognostic parameter. The tumor-stroma ratio (TSR) was previously validated by international research groups as a robust parameter with good interobserver agreement.

Objective: The Uniform Noting for International Application of the Tumor-Stroma Ratio as an Easy Diagnostic Tool (UNITED) study was developed to bring the TSR to clinical implementation.

Heparins: A Shift of Paradigm.

Heparins inhibit the thrombin forming capacity of plasma, i. e., the endogenous thrombin potential (ETP), by their anti-thrombin (aIIa) activity, the anti-factor Xa (aXa) activity is of minimal importance.

A reduction of prothrombin conversion by cardiac surgery with cardiopulmonary bypass shifts the haemostatic balance towards bleeding.

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with blood loss and post-surgery thrombotic complications. The process of thrombin generation is disturbed during surgery with CPB because of haemodilution, coagulation factor consumption and heparin administration. We aimed to investigate the changes in thrombin generation during cardiac surgery and its underlying pro- and anticoagulant processes, and to explore the clinical consequences of these changes using in silico experimentation.

Differences in the mechanism of blood clot formation and nanostructure in infants and children compared with adults.

Introduction: Infants and children have a lower incidence of thrombosis compared with adults. Yet, the mechanism of blood clot formation and structure in infants and children, as the end product of coagulation, has not been studied. This study aimed to establish differences in the mechanism of thrombin generation, fibrin clot formation and response to thrombolysis in infants and children compared with adults.

Thrombin Generating Capacity and Phenotypic Association in ABO Blood Groups.

Individuals with blood group O have a higher bleeding risk than non-O blood groups. This could be explained by the lower levels of FVIII and von Willebrand Factor (VWF) levels in O individuals. We investigated the relationship between blood groups, thrombin generation (TG), prothrombin activation and thrombin inactivation.

Measurement of thrombin generation intra-operatively and its association with bleeding tendency after cardiac surgery.

Introduction: Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are susceptible to haemostatic disturbances. Monitoring the haemostatic capacity by conventional clotting tests is challenging.

Materials And Methods: Thrombin generation (TG) by Calibrated Automated Thrombography, clotting tests and tissue factor pathway inhibitor (TFPI) measurements were performed to describe the relationship between haemostatic changes and alterations in these tests.

New insights into the role of erythrocytes in thrombus formation.

The role of erythrocytes in thrombus formation has previously been regarded as passive by their influence on rheology. Erythrocytes are known, due to their abundance and size, to push platelets to the vascular wall (laminar shearing). This results in an increased platelet delivery at the vascular wall enabling platelets to seal off a vascular damage preventing excessive blood loss.

Preoperative thrombin generation is predictive for the risk of blood loss after cardiac surgery: a research article.

Background: In this study the value of thrombin generation parameters measured by the Calibrated Automated Thrombography for prediction of blood loss after cardiac surgery with cardiopulmonary bypass was investigated.

Methods: Thirty male patients undergoing first-time coronary artery bypass grafting were enrolled. Blood samples were taken pre-bypass before heparinisation (T1) and 5 min after protamine administration (T2).

Large inter-individual variation of the pharmacodynamic effect of anticoagulant drugs on thrombin generation.

Anticoagulation by a standard dosage of an inhibitor of thrombin generation presupposes predictable pharmacokinetics and pharmacodynamics of the anticoagulant. We determined the inter-individual variation of the effect on thrombin generation of a fixed concentration of direct and antithrombin-mediated inhibitors of thrombin and factor Xa. Thrombin generation was determined by calibrated automated thrombinography in platelet-poor plasma from 44 apparently healthy subjects which was spiked with fixed concentrations of otamixaban, melagatran, unfractionated heparin, dermatan sulfate and pentasaccharide.

Thrombin generation: what have we learned?

Thrombin is a pivotal player in the coagulation system. In clotting blood a transient wave of thrombin appears after a lag time. Clotting occurs at the start of the wave.

High subretinal fluid procoagulant activity in rhegmatogenous retinal detachment.

Purpose: An increased mRNA expression of genes related to blood coagulation has been demonstrated in an experimental retinal detachment model but has not yet been confirmed in human clinical specimens. Tissue factor (TF), the initiating factor of blood coagulation, may be a determinant of the extent of tissue injury after rhegmatogenous retinal detachment (RRD). This study was conducted to determine whether subretinal fluid and vitreous fluid collected from patients with RRD have a procoagulant effect.

The technique of measuring thrombin generation with fluorescent substrates: 4. The H-transform, a mathematical procedure to obtain thrombin concentrations without external calibration.

In fluorogenic thrombin generation (TG) experiments, thrombin concentrations cannot be easily calculated from the rate of the fluorescent signal increase, because the calibration coefficient increases during the experiment, due to substrate consumption and quenching of the fluorescent signal by the product. Continuous, external calibration via an in a parallel sample therefore was hitherto required for an accurate calculation of the TG curve. A technique is presented that allows mathematical transformation of experimental fluorescence intensities into "ideal" data, i.

The technique of measuring thrombin generation with fluorogenic substrates: 1. Necessity of adequate calibration.

In fluorogenic thrombin generation (TG) measurement the concentrations of thrombin are obtained from the course of fluorescence intensity. Because of fluorescence quenching, in one series of normal plasmas (n = 60), the rate of fluorescence increase at fixed thrombin activity was 70 +/- 13% of that in buffer, in another (n = 139) 75 +/- 8%. Using a calibration factor (CF) measured in buffer therefore underestimates thrombin concentrations in plasma and introduces a source of error.

Linear diffusion of thrombin and factor Xa along the heparin molecule explains the effects of extended heparin chain lengths.

Question: How does the size of the heparin moiety in the anti-thrombin (AT)-heparin complex influence its anticoagulant properties?

Approach: Of 52 heparin fractions of precise Mr between 2800 and 37,000 we determined the dissociation constant (Kd) of the binding of the enzyme to the AT-heparin complex and the decay constant (kdec) of thrombin and factor Xa at 1 microM of that complex.

Results: The Kd of thrombin or factor Xa is constant when expressed in terms of the concentration of sugar units, i.e.

Thrombin generation, a function test of the haemostatic-thrombotic system.

By the use of a fluorogenic thrombin substrate and continuous calibration of each individual sample, it is now possible to obtain a thrombin generation (TG) curve (or thrombogram) in plasma, with or without platelets, in an easy routine procedure at high throughput and with an acceptable experimental error (<5%). Evidence is growing that the parameters of the thrombogram, and notably the area under the curve (endogenous thrombin potential, ETP), are useful in assessing bleeding- or thrombotic risk and its modification by antithrombotic- or haemostatic treatment. Available data strongly suggest that conditions (congenital, acquired, drug-induced) that increase TG all cause a thrombotic tendency and that conditions that decrease TG prevent thrombosis but, beyond a limit, cause bleeding.

Evaluation of thrombin generating capacity in plasma from patients with haemophilia A and B.

In haemophilia patients, a relationship is usually observed between the clinical expression of the disease and plasmatic factor VIII/factor IX (FVIII/FIX) activity. However, it is known from clinical experience, that some haemophilia patients, despite similar FVIII/FIX plasma levels, could exhibit different bleeding phenotype. After determining preanalytical test conditions, we evaluated the thrombin generation capacity from haemophilia plasma samples in various conditions and the potential usefulness of thrombin generation test (TGT) in haemophilia patients.

Thrombin generation assays: accruing clinical relevance.

Purpose Of Review: After decades of near oblivion, thrombin generation is being revived as an overall function test of the plasmatic coagulation system in platelet-poor plasma (PPP). In platelet-rich plasma (PRP) it assesses platelet procoagulant functions as well.

Recent Findings: The recently developed use of special fluorogenic thrombin substrates allows monitoring of thrombin concentration in clotting PPP and PRP on line in up to 24 parallel samples.