Saliva, as a pooled sample, contains specific biomarkers for unique pathological aspects of periodontal disease, such as interleukin-1β (IL-1β), IL-6, IL-8, IL-11 and tumor necrosis factor-alpha (TNF-α) (Graves, 2008; Rathnayake et al., 2017). The gene discussed is TNF; the disease is periodontal disorder.