A lower ghrelin concentration in the serum of patients from the study group in comparison with the control may be a result of the fact that a significant portion of patients with HNSCC declared that they are both active alcohol drinkers and cigarette smokers, which are factors irritating the mucous membrane of the stomach and that have a potential connection with the development of chronic gastritis, Helicobacter pylori infection, and thus to a certain degree an induction of cancerous changes in this organ [71,72]. Here, GHRL is linked to head and neck squamous cell carcinoma.