Potential Markers from Serum-Purified Exosomes for Detecting Oral Squamous Cell Carcinoma Metastasis

Background: Blood contains exosomes that are related to tumor cells. Those exosomes can regulate communication between cells and have a great influence on a variety of tumor-associated proceedings through their target cells. Therefore, serum exosomes (SE) were supposed to play a crucial role in cancer development. Methods: This study presented a quantitative proteomics analysis to identify the protein content in SEs including 30 subjects from oral squamous cell carcinoma (OSCC) patients with lymph node metastasis (LNM), OSCC patients with no LNM (NLNM), and healthy controls (HC). Differentially expressed proteins (DEP) were analyzed by bioinformatics, and then a total of 30 subjects were used for Western blot and 60 subjects for IHC, ELISA, and RT-PCR verifications. The correlations were assessed between DEP expression and clinicopathologic factors. Results: A total of 415 proteins were identified. Comparing with HC and OSCC- NLNM, we found 37 proteins and 28 proteins in the SEs of OSCC-LNM, respectively. There were significant correlations among the expression of PF4V1 with tumor differentiation level, PF4V1 and F13A1 with the number of positive nodes, and ApoA1 with smoking and drinking. ROC curve analysis indicated that the combinations of the different biomarkers or specimen were obviously superior to single biomarker or specimen for diagnosing OSCC-LNM. Conclusions: We conclude that PF4V1, CXCL7, F13A1, and ApoA1 from SEs may be related to the metastasis of OSCC, which would be helpful in the diagnosis of OSCC-LNM. Impact: Biomarkers from SEs could help with the diagnosis of metastasis in OSCC.