Evaluation of E-cadherin, β-catenin and vimentin protein expression using quantitative immunohistochemistry in nasopharyngeal carcinoma patients.

Purpose: Aberrant expression of proteins involved in epithelial-to-mesenchymal transition have been described in various cancers. In this retrospective study, we sought to evaluate E-cadherin, β-catenin and vimentin protein expression in non-metastatic nasopharyngeal (NPC) patients treated with curative intent, examine their relationship with each other, and with clinical outcome measures.

Methods: Pre-treatment formalin-fixed paraffin-embedded biopsies of 140 patients treated between January 2000 and December 2007 were assembled into a tissue microarray (TMA). Automated quantitative immunohistochemistry (AQUA®) was performed on sequential TMA sections stained with fluorescent-labeled antibodies against E-cadherin, β-catenin and vimentin. Cox proportional hazards regression was used to estimate the effect of cytoplasmic vimentin, cytoplasmic E-cadherin, β-catenin nuclear/cytoplasmic ratio expression on overall survival and disease-free survival.

Results: The average age of the patients was 51.7 years (SD=12.1; range 18-85), 66% were male, 71% had a KPS ≥ 90% at the start of treatment and 65% had stage III/IV disease. After adjusting for performance status, WHO and stage, high E-cadherin levels over the 75th percentile were found to produce a significantly increased risk for both a worse overall survival (HR = 2.53, 95% CI 1.21, 5.27) and disease free survival (DFS; HR = 2.14, 95%CI 1.28, 3.59). Vimentin levels over the first quartile produced an increased risk for a worse DFS (HR = 2.21, 95% CI 1.11, 4.38). No association was seen between β-catenin and survival.

Conclusion: In this cohort of NPC patients, higher levels of E-cadherin and higher levels of vimentin were associated with worse outcomes. Further work is needed to understand the role of these epithelial mesenchymal transition proteins in NPC.