Clinical significance of interleukin-6 and interleukin-6 receptor expressions in oral squamous cell carcinoma

Background. Recent studies showed that interleukin-6 (IL-6) played a role in tumor development. However, available information about the prognostic significance of IL-6 and IL-6 receptors (IL-6R) for oral squamous cell carcinoma (OSCC) is limited. Methods. Eighty-six patients with OSCC were enrolled. Immunohistochemical staining was used to determine IL-6R expression and in-situ hybridization for IL-6 mRNA transcripts in surgical specimens. Clinicopathologic correlation was evaluated by chi-square test and survival by log rank test. Results. Expression rates of IL-6R and IL-6 mRNA transcripts in tumor specimens were 73.3% and 54.7%, much higher than those in nontumor mucosa (p <.001). IL-6R overexpression was associated with larger tumors and more advanced histologic grade (p <.05). The presence of IL-6 mRNA transcripts was inversely correlated with distant metastasis, lymph node involvement, and second primary SCC (p <.05) and predicted better survival (p = .007). Conclusions. IL-6-IL-6R coexpression was rather high in OSCC, and IL-6 mRNA transcript expression might influence patient survival. The biologic role of IL-6-IL-6R coexpression in OSCC needs additional investigation.