Among the proteins not secreted by the salivary glands, this study highlighted a higher level of proteins with a multifaceted nature, namely, S100A8 and S100A9, α-defensins 1–4, Tβ4, and cystatins A and B. They are involved in many biological functions also at the level of the nervous system, and thus, it is not surprising that they may be implicated in molecular processes associated with AD pathogenesis. The gene discussed is S100A9; the disease is Alzheimer disease.