S100 calcium binding protein expression in nasopharyngeal carcinoma, sinonasal papilloma and upper respiratory tract mucosa

Objectives: The S100 calcium binding protein P (S100P) is a small member of the S100 protein family that is considered to play a role in carcinogenesis and has been shown to be overexpressed in some carcinomas. In this study, we aimed to evaluate an immunohistochemical (IHC) analysis of S100P expression in nasopharynx carcinoma (NPC), sinonasal papilloma (SNP) and upper respiratory mucosae. Design: Prospective cross-sectional study Setting: Department of Pathology, Faculty of Medicine, University of Van Yuzuncu Yil, Van, Turkey Subjects: Sixty-eight samples including NPC, SNP and nonneoplastic upper respiratory tract epithelia were included in the study. Interventions: Samples stained with the S100P primary antibody using the IHC method. Main outcome measures: The staining scores and intensities were calculated based on nuclear or nuclear/cytoplasmic staining. Results: S100P staining was not detected in 17 out of 19 NPC cases but was detected in the epithelium of all cases of SNP and non-neoplastic upper respiratory tract. A significant difference was found among the groups regarding staining score and intensity. Conclusion: Considering that S100P was not expressed in NPC but was expressed in the epithelium of normal nasopharynx, it can be asserted that our results indicated the loss of S100P expression in NPC. Our results also indicated that S100P, which is known to be expressed in urothelium, was also expressed in the upper respiratory tract epithelia.