UCHL1 and parathyroid gland carcinoma: Some studies assessed the role of additional molecular marker to complement parafibromin staining in the screening process, emerging the protein 9.5 (PGP9.5) encoded by the ubiquitin carboxyl-terminal esterase L1 (UCHL1), that was found to be upregulated in the majority of parathyroid carcinomas [46].