Secreted vesicles have had a rather a mixed press in cancer biology. Originally considered as a ‘cellular trashcan’, with particular usefulness as a repository for specific proteins from the originating cell type, the literature now abounds with papers describing the usefulness of exosomes: one class of secreted vesicles. Now, a potent function has been assigned to these small (30-100nm) vesicular particles, which carry a variety of macromolecular cargoes, including proteins and various forms of RNA. When secreted from cancer cells into prostate cancer patients’ serum, it is likely that the ‘exosomal signature’ can be exploited as a useful diagnostic tool. Indeed, there are strong arguments that many traditional ‘serum’ and urinary markers for cancer are actually present in the exosomal fraction, which performs not as a trashcan, but more as a protective envelope for labile molecules such as mRNA and miRNA.