CD80 and oral cavity squamous cell carcinoma: Multifunctional P. melaninogenica in saliva is also associated with oral squamous cell carcinoma [28] and is causative of periodontitis [29], Alzheimer’s disease mortality [30], hyperglycemia [31], [and MHCII, CD80 and IFN-γ upregulation in salivary gland epithelial cells in Sjögren’s syndrome [32].