PSMA5 and plasma cell myeloma: PSMA5 encodes one of the α subunits of the 20S proteasome and Zhu and coworkers recently demonstrated that knocking down proteasome genes, including PSMA5, could negatively impact the inhibitory effects of bortezomib on growth [46], suggesting PSMA5 transcription could be a key target for anti-myeloma SP therapy.