A Potential biomarker for the early diagnosis of OSCC: saliva and serum PrP C .

Background: Oral squamous cell carcinoma (OSCC) is frequently diagnosed at an advanced stage, and the high mortality of patients is mainly due to the delay of diagnosis. Cellular prion protein (PrP ^C ) contributes to the occurrence and development of many malignant tumors. However, little has been known about the clinical and diagnostic value of PrP ^C in OSCC. This study investigated the levels of PrP ^C in the saliva and serum of patients with OSCC, OPMD and control group and their diagnostic value. Methods: The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and Clinical Proteome Tumor Analysis Consortium (CPTAC) databases were analyzed to evaluate the expression of human prion protein gene ( PRNP ) mRNA and PrP ^C in OSCC. Enzyme-linked Immunosorbent Assay (ELISA) was utilized to detect the expression of PrP ^C in saliva and serum samples of OSCC, OPMD and control groups. Furthermore, diagnostic value and clinical significance of PrP ^C in OSCC was identified. Protein-protein interaction (PPI) network was constructed by STRING. GO and KEGG analysis were performed by ClusterProfiler. Results: The levels of PRNP mRNA and PrP ^C in OSCC were significantly higher than those in the control group from databases ( P <0.05). Besides, salivary and serum PrP ^C of OSCC patients showed increased levels compared with OPMD and control groups ( P <0.05). The expression of salivary and serum PrP ^C of OSCC was correlated with the degree of differentiation ( P <0.05), and the expression of PrP ^C from CPTAC was related to tumor stage of OSCC ( P <0.05). The areas under the diagnostic curves (AUCs) of salivary and serum PrP ^C were 0.807 and 0.671, respectively. GO and KEGG analysis revealed that PrP ^C might be related to cell adhesion, cell differentiation, signal transduction and apoptosis, and participate in the pathways of focal adhesion, PI3K-Akt signaling pathway and ECM- receptor interaction in OSCC. Conclusion: PrP ^C in saliva and serum may be a potential biomarker for early diagnosis of OSCC.
Competing Interests: Competing Interests: The authors have declared that no competing interest exists.
(© The author(s).)