BAG6 and neoplasm: Because the HLA-restricted anti-tumor epitope peptide PSCA (amino acids 14-22) contains a cleavage site for the ER signal peptidase57, and because PSCA protein contains a highly hydrophobic stretch at its C-terminus, as in other known BAG6-preferring clients, an interesting challenge for the future will be to determine whether mislocalized SS-uncleaved membrane protein species might be general clients for the BAG6-mediated protein quality control machinery.