Effects of platelets on cancer progression.

Platelets are small (2-4 μm), anucleate, hematopoietic cells released by bone marrow megakaryocytes in the bloodstream. For a long time, platelets were described as the major effectors of hemostasis and thrombosis. In 1865, Armand Trousseau demonstrated a close relation between thrombosis and cancer. Subsequently, much clinical and experimental evidence supports the idea that platelets play several roles in the progression of malignancies and in cancer-associated thrombosis. In this review, we will discuss the roles of tumor-educated platelets (TEPs) in the progression of cancer from primary tumors to secondary metastatic outbreaks.