Salivary chemical barrier proteins in Oral Squamous Cell Carcinoma – Alterations in the defense mechanism of the oral cavity

Oral squamous cell carcinoma (OSCC) is one of the most frequent type of head and neck cancers. Despite the genetic and environmental risk factors, OSCC is also associated with microbial infections and/or dysbiosis. The secreted saliva serves as the chemical barrier of the oral cavity and since OSCC can alter the protein composition of saliva, our aim was to analyze the effect of OSCC on the salivary chemical barrier proteins. Publicly available datasets regarding the analysis of salivary proteins from patients with OSCC and controls were collected and examined in order to identify differentially expressed chemical barrier proteins. The network analysis and gene onthology (GO) classification of the differentially expressed chemical barrier proteins were performed, as well. 127 proteins showing different expression pattern between the OSCC and control groups were found. The protein-protein interaction network of up- and down-regulated proteins were constructed and analyzed. The main hub proteins (IL-6, IL-1B, IL-8, TNF, APOA1, APOA2, APOB, APOC3, APOE, and HP) were identified and the enriched GO terms were examined. Our study highlighted the importance of the chemical barrier of saliva in the development of OSCC.