Expression of interleukin-6 in ocular surface squamous neoplasia

Purpose: Interleukin-6 (IL-6) is an important cytokine in the cascade of inflammation and cancer progression. The aim of this study was to identify IL-6 expression in ocular surface squamous neoplasia (OSSN) in comparison with non-neoplastic conjunctival tissue. Methods: Twenty paraffin-embedded tissue sections of conjunctiva from patients with OSSN including conjunctival intraepithelial neoplasia (CIN) in all grades of severity and squamous cell carcinoma (SCC) were assessed by immunohistochemistry staining for IL-6. Twenty non-neoplastic conjunctival sections from age matched patients were selected as the control group. Tissues with more than one focus of inflammatory cell infiltration were excluded from the study. The mean area of positive staining was recorded and the intensity of staining was scored in both groups and compared by statistical methods. Results: The mean staining area in the dysplasia group was significantly more than non-neoplastic conjunctival tissue (63.5±25.96 and 30±15.98 percent respectively; P-value of <0.0001). Nuclear staining was observed in both groups and the difference was not statistically significant. Conclusion: IL-6 expressed more in the dysplastic group in compare to non-neoplastic conjunctiva and can therefore be used to diagnose dysplastic state of the conjunctiva; however, in our study, intensity of staining does not correlate with the severity of dysplasia statistically; most probably because of a low sample size in each category. The role of nuclear staining is not clear. Our findings can be an introduction toward targeted treatment of ocular surface neoplasia by the aim of newer anti-IL agents. Further investigation is needed.