Objective: To investigate the expression of 14-3-3ε in esophageal squamous cell carcinoma (ESCC) and relationship of 14-3-3ε and clinicopathological factors of ECSS patients.
Methods: The 14-3-3ε expression in tumors and adjacent normal epithelia from 72 ESCC patients was detected by immunohistochemical staining. Correlations of 14-3-3ε expression or their subcellular localization and clinicopathological factors were analyzed using Chi-squared test. Survival curves were generated according to the Kaplan-Meier method, and the statistical analysis was performed by Log-rank test.
Results: The expression of 14-3-3ε protein was significantly up-regulated in tumors with 77.8% positive and 27.8% strong positive staining, compared with paired adjacent normal epithelia with 43.1% positive and only 2.8% strong positive staining (P < 0.01). In a total of 56 positive staining tumors, 14-3-3ε was detected in cytoplasm of 37 (66.1%), in nucleus of 4 (7.1%), in both cytoplasm and nucleus of 15 (26.8%) cases. Whereas, in a total of 31 positive staining normal epithelia, 14-3-3ε was detected in cytoplasm of 0, in nucleus of 13 (41.9%), in both cytoplasm and nucleus of 18 (58.1%) cases (P < 0.01). Statistical analysis revealed that strong 14-3-3ε expression was correlated with lymph node metastasis (P = 0.028) and lower 5-year survival (P = 0.018). The survival curves calculated by Kaplan-Meier method further showed that the patients with strong 14-3-3ε expression had a shorter survival than patients with negative or weak 14-3-3ε expression (Log-rank, P = 0.031). No correlation was found between subcellular localization of 14-3-3ε in tumor cells and clinicopathologic factors and prognosis of ESCC patients.
Conclusion: The 14-3-3ε expression is significantly up-regulated in ESCCs. It was usually located in cytoplasm of tumor cells, but nucleus of normal epithelia. Strong expression of 14-3-3ε in tumors is associated with lymph node metastasis and considered as an poor prognostic factor for ESCC.