Evaluation of pre and postoperative inflammatory biomarkers through proximity extension assay in tongue squamous cell carcinoma

Background Although prognostic biomarkers in patients with oral squamous cell carcinoma (SCC) have previously been explored, none have yet been established for clinical use for oral SCC. This study evaluated plasma inflammatory cytokines using the proximity extension assay (PEA) in patients with tongue SCC before and after surgery to investigate relationships between disease status and cytokine levels. Methods Plasma samples from 19 patients who underwent surgery for tongue SCC were collected pre- and postoperatively. Inflammatory cytokine levels were quantified by PEA. Cytokine levels were compared between preoperative patients with early- and advanced-stage cancer, patients with recurrence after surgery and with no recurrence, and as well as between patients of each stage grouped by prognosis. Results: No difference in preoperative cytokine levels was found between early- and advanced-stage patients. Levels of fms-related receptor tyrosine kinase 3 ligand (FLT3LG) were significantly lower in the postoperative recurrent group as compared with the nonrecurrent group (p = 0.049). Amongst the advanced-stage patients with recurrence or metastasis in postoperative, the reduction in interleukin-6 (IL-6), hepatocyte growth factor (HGF), and tumor necrosis factor (TNF) levels following surgery was less pronounced compared with the patients with no evidence of disease. (IL-6: p = 0.037, HGF: p = 0.020, TNF: p = 0.037). Conclusions We identified FLT3LG, IL-6, HGF, and TNF as potential inflammatory biomarkers to evaluate disease status and prognosis in patients with tongue SCC by PEA technology.