We provide evidence here of a central role for PAI-1 in the platelet-cancer cell interactome by interrogating the synergistic pressures that PAI-1 and platelets exert in both the tumor microenvironment and in the circulation, and by investigating how these may contribute to the differential gene expression of PAI-1 in the contexts of OC metastasis and patient prognosis. This evidence concerns the gene SERPINE1 and cancer.