RPLP0 and neoplasm: However, it is possible that this signature is still unique to OS, as a study that profiled OS tumour tissue found an upregulation of 60S acidic ribosomal protein P0, proteasome subunits β type-4 (PSMB4) and β type-6 (PSMB6), and a signature relating to unfolded protein response which is targetable by proteasome inhibitors [76].