When HNSCC tumors are considered separately according to their primary site, the correlation of LSD1 expression with advanced tumor stage can be observed exclusively in tumors of the hypopharynx (T stage: p = 9.5 × 10−4, UICC: p = 0.020), whereas no significant differences dependent on tumor stage (T, UICC) were observed in tumors of the other primary sites. This evidence concerns the gene KDM1A and head and neck squamous cell carcinoma.