human hsp60, the product of the hspd1 gene, is a group i mitochondrial chaperonin, phylogenetically related to bacterial groel. recently, the presence of hsp60 outside the mitochondria and outside the cell, e.g. in circulating blood, has been reported [1], [2]. although it is assumed that hsp60 extra-mitochondrial molecule is identical to the mitochondrial one, this has not yet been fully elucidated. despite the increasing amount of experimental evidences showing hsp60 outside the cell, it is not yet clear how general this process is and what are the mechanisms responsible for hsp60 translocation outside the cell. neither of these questions has been definitively answered, whereas there is some information regarding extracellular hsp70. this chaperone was also classically regarded as an intracellular protein like hsp60, but in the last few years considerable evidences showed its pericellular and extracellular residence