THBS1 and cancer: The expression levels of 11 genes (THBS1, PF4, TIMP3, VWF, ITGB3, F2, COMP, GP1BA, PLEK, RAPGEF3 and GNB2, later referred to as the “platelet signature”) were significantly higher in CTCs compared to cancer cells from “solid” metastases (Figure 4B).