PF4 and neoplasm: Of note, ASP treatment did not affect Pf4 expression in the CT26 tumor (Supplementary Fig. S6G) even though this reduced plasma Pf4 levels (Supplementary Fig. S6H), confirming that platelet Pf4 is not responsible for the increased Pf4 gene expression in the tumor microenvironment, and suggesting that the effects of exercise on Pf4 expression must be occurring in tumor cells, or in tumor-associated macrophages than in intratumoral platelets.