We show for the first time that inhibition of this release through pretreatment of PCa PC3 cells with the membrane-permeant calpain inhibitor, CP, or by silencing the calpain gene, results in elevated levels of intracellular DTX, as had been previously suggested might happen for cytotoxic drugs in tumor cells treated with inhibitors of MV biogenesis32 and we showed recently with a novel inhibitor of microvesiculation33. This evidence concerns the gene CP and neoplasm.