Total peripheral blood extracellular vesicles, observed by nanoparticle tracking analysis of platelet-poor plasma, increased substantially in tumor-bearing mice of both genotypes at d21, in particular large extracellular vesicles > 150 nm in diameter that likely include microvesicles (microparticles), but we did not observe significant differences in extracellular vesicle concentrations between Pf4-Cre and Dicer1fl/fl/Pf4-Cre tumor-bearing mice. Here, PF4 is linked to neoplasm.