TFPI and cancer: Moreover, increased levels of TFPI have been noted in the plasma of cancer patients,25,26 reflecting, possibly, induction of heparanase expression and elevation of its plasma levels revealed by ELISA assay.28 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.