Stratified analysis of the five-proteins signature for HNSCC patients in the TCPA validation cohort with age, gender, tumor grade or TNM stage. The patients with high-risk scores have significantly worse OS than those with low-risk scores in the subgroups of age<60, male, grade 1-2 and stage III-IV. No significant difference in OS is found for the patients in the subgroups of age>=60, female, grade 3-4 and stage I-II (A–D).