Studies have shown that levels of specific proteins like vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), and platelet factor 4 (PF4) were higher in the platelets of 35 cancer patients compared to 84 healthy individuals, as measured by a technique called enzyme-linked immunosorbent assay (ELISA) [119]. This evidence concerns the gene PF4 and cancer.