Occludin and claudin-1 are potential prognostic biomarkers in patients with oral squamous cell carcinomas: An observational study.

Objectives: The objective of this study was to evaluate the expression of several cell membrane markers in oral squamous cell carcinomas (OSCC) and to examine their prognostic influence.

Study Design: We analyzed the immunohistochemical expression of claudin-1 (CLDN-1), claudin-4 (CLDN-4), claudin-5 (CLDN-5), claudin-7 (CLDN-7), occludin (OCLN), and E-cadherin (CDHE) in 60 patients with OSCC treated in a central hospital Center of Oporto. The prognostic significance of these biomarkers in cancer-specific survival and recurrence-free survival were evaluated using multivariate analysis.

Results: Claudin-1 was observed in the membrane of tumor cells in 51 cases (89.5%), CLDN-4 in 36 cases (63.2%), and CLDN-7 in 48 cases (80%). Claudin-5 was detected in the cytoplasm of tumor cells in 46 cases (78%) and OCLN in 40 cases (70.2%). In a multivariate analysis, the combined evaluation of OCLN and CLDN-1 revealed a significant and independent association with cancer-specific survival and recurrence-free survival. We found a low extent score for OCLN and a high intensity score for CLDN-1, presenting the hazard ratios of 15.48 (P = .014) and 9.446 (P = .012), respectively.

Conclusion: The CLDN-1 and OCLN proteins could be involved in tumor progression of OSCC. Their combined deregulated expression showed an adverse effect on survival and therefore they could be regarded as important prognostic biomarkers in OSCC.