The dynamic crosstalk between cancer and platelet is increasingly recognized as a key regulator of malignant progression.Tumor cells are known to secrete several cytokines,which activate platelet and induce tumor thrombus formation.In turn,activated platelets provide instructive signals that affect tumor cell behavior and metastatic potential.One of the main markers for platelet activation is P-selectin,and platelet-tumor cell interactions and the signaling pathways that P-selectin trigger are therefore crucial determinants of cancer metastasis and potential target for anti-metastatic therapies.