TF and cancer: Moreover, increased levels of TFPI have been noted in the plasma of cancer patients,62,63 reflecting, possibly, induction of heparanase expression and elevation of its plasma levels revealed by a newly developed ELISA assay.65 In human umbilical vein endothelial cell (HUVEC) and tumor-derived cell lines, release of TFPI from the cell surface correlated with enhanced TF-mediated coagulation.