Tissue factor expression determines tumour cell coagulation kinetics

Introduction: Cancers are associated with varying degrees of an increased risk of venous thromboembotic events (VTE) occurring. This increased risk is tumour driven and associated with tumour expression of tissue factor (TF) and tumour‐derived microparticles (MP). In this study, cancer cell lines from phenotypically distinct tumours were assessed for cell surface TF expression and prothrombin time (PT) taken as a measure of procoagulant potential. Methods: Breast (T47D, MCF‐7), colorectal (Colo320 and LoVo), head and neck (USCC 11b, 12, 81b and SIHN‐011A) and pancreatic tumour cell lines (ASPC‐1 and CFPAC‐1) were assessed for TF expression by flow cytometry and relative mean fluorescence determined. Procoagulant potential of the cells was then determined by PT assay. Results: Cell‐supported coagulation was shown to be cell number dependent, defined by a logarithmic relationship that was consistent across all cell lines. Single cell PT was determined for each cell line from the slope of a logarithmically transformed data plot. A near linear relationship was observed between TF expression and single cell clotting time where a higher expression of TF results in a proportionally faster PT (P < 0.001). Conclusions: This study shows that across a range of tumour sites a consistent relationship is seen between procoagulant potential and both cell number and TF cell surface expression.