HLA-G and head and neck squamous cell carcinoma: The concentration of sHLA-G (8.25 ± 1.74 ng/μl), IL-10 (43.99 ± 11.13 ng/μl) and IFN-γ (20.04 ± 9.70 ng/μl) protein levels were higher in serum of HNSCC patients in comparison to controls (sHLA-G: 6.45 ± 1.31; IL-10:37.08 ± 8.55; IFN-γ:16.19 ± 6.60 ng/μl).