Selected peptides from the 15 immune and microenvironment candidate markers were detected in the buffy coat HNSCC cohort, whereas for saliva samples only the peptides SRSF3_Pep1, SRSF5_Pep1, SRSF5_Pep2, CD45_Pep1, and CD4_Pep1 could not be confidently measured due to low signal-to-noise ratios (Supplementary Data 4-2–4-6; Supplementary Data 7-2 – 7-4). This evidence concerns the gene CD4 and head and neck squamous cell carcinoma.