PSME1 and head and neck squamous cell carcinoma: Characteristics indicative of the prognostic outcomes in the TCGA-HNSCC training set were developed based on the expressions of the characterized genes and the regression coefficients as described below: Riskscore = (-0.685*ICOS) +0.749*PSME1 + 0.25*SERPINA1 + 0.41*SH3KBP1 + 0.24*SP100+(-0.368*ZAP70).