Several lines of evidence show that the cross-talk of cancer cells with stromal cells (such as immune cells and fibroblasts) and platelet-derived products induce a novel phenotype, which allows them to invade the healthy tissue around, to enter the bloodstream and to colonize distant tissues. The role of platelets in conditioning tumor microenvironment, by releasing several bioactive mediators and microvesicles, is increasingly recognized. Platelets and cancer cells have been shown to release a significant amount of ATP and ADP (Beigi et al., 1999; Pellegatti et al., 2008; Burnstock and Di Virgilio, 2013).