Abstract
The PA of GC, CC, and RC extracts was assayed by the recalcification of human normal or F VII-DP, and the PA of normal tissue was also determined. The PA of normal tissue was higher than that of the cancer tissues in all groups of specimens. Substitution of normal plasma by F VII-DP resulted in significant depression of the PA and the differences in the PA between the normal and cancer tissue samples disappeared. Preincubation of normal and cancer tissue extracts with the cysteine proteinase inhibitors, mercuric chloride and iodoacetamide, did not affect the PA of these extracts. We conclude that the PA of the investigated cancer extracts is factor VII-dependent and can be related to the presence of tissue factor within cancer tissue.