Given these different findings, we decided to quantitate in a cohort of patients with HNSCC: (i) 18F-FDG-uptake, reflecting glucose consumption of the entire solid tumor mass, (ii) levels of the β-F1-ATPase and the BEC index within tumor cells as well as (iii) levels of representative subunits of the ETC, i.e. NDUF-S1 (Complex I) and COX1 (Complex IV). This evidence concerns the gene NDUFS1 and head and neck squamous cell carcinoma.