Level of PSDM1 expression correlates with treatment outcome. HNSCC tissue micro arrays were stained for PSMD1 to evaluate the expression of this proteasome subunit. The intensity of the staining was evaluated independently by two pathologists. (a) Pictures of representative staining for PSMD1 show the 3 different levels of staining. Overall survival (b) and loco-regional control (c) for patients receiving primary definitive radiotherapy. (d) Overall survival for patients receiving postoperative radiotherapy.