PF4 and neoplasm: A growing body of evidence reported that high PLR can activate the invasiveness of tumor cells by enhancing the formation of tumor stoma and supporting the stable adhesion of tumor cells to the endothelium.24 In addition, platelets could secrete cellular growth factors such as platelet‐derived growth factor, vascular endothelial growth factor, transforming growth factor beta, platelet factor 4, and then stimulate tumor angiogenesis and growth.25