TF and cancer: As the presence of procoagulant TF on tumour cells does not explain why thrombosis typically occurs at sites distant from the primary tumour, it has been hypothesised that TF borne by circulating microvesicles might be a contributing factor.56 Indeed, cultured TF-expressing cancer cells can release TF-bearing microvesicles into the culture supernatant, and TF-expressing tumours release TF-positive microvesicles into the blood.