Blood platelets regulate wound healing, but increasing evidence suggest that paradoxically, platelets also support tumor growth and metastasis. In this project, we will find out how platelets and cancer cells exchange information via extracellular vesicles (EVs), with the hypothesis that tumor cells and their EVs activate and reprogram platelets into promoting cancer progression and metastasis. Analysis of the composition of the released EVs from the tumor-educated platelets and elucidating the affected signaling pathways in the cancer cells will provide both insight into how a tumor hijacks platelet functions, and candidates for biomarkers which will be searched from the blood of cancer patients. How tumor-educated EVs compared to normal platelet EVs are preferably taken up by cancer cells will provide candidates for novel drug delivery systems. In all, this novel angle to cancer progression will provide improved insight and innovative weapons to help fight cancer.