Altered Localization of p120 Catenin in the Cytoplasm Rather than the Membrane Correlates with Poor Prognosis in Esophageal Squamous Cell Carcinoma

BACKGROUND: P120 catenin (p120ctn), a regulator of cell adhesion, has previously been found in many malignancies, and suggested a role in invasion, metastasis and survival. The aim of this study was to investigate correlations between altered localization of p120ctn and clinical-pathological characteristics in esophageal squamous cell carcinoma (ESCC). METHODS: Immunohistochemical staining for p120(ctn) was performed on tissue samples from 118 patients with ESCC. The expression of p120(ctn) was scored for intensity and cellular localization by Image-pro Plus 6.0. Correlations between immunohistochemical staining of p120(ctn) and pathological characteristics and clinical prognosis were determined using SPSS 18.0 software. RESULTS: Membrane expression of p120(ctn) in ESCCs was lower than that in adjacentnormal esophageal epithelial tissues (P = 0.041), while overall cellular expression of p120(ctn) was not different between the two tissue types (P = 0.787). Furthermore, neither overall cellular expression nor localized membrane expression was associated with histological and clinical variables. The high ratio of membrane expression to overall cellular expression (M/C) of p120(ctn) was inversely associated with lymph node invasion (P = 0.001), tumor differentiation (P = 0.012) and advanced tumor stage (P = 0.005); however, it was poorly associated with T stage (P = 0.274). The high M/C ratio of p120(ctn) was inversely correlated with poor survival; the 5-year OS (overall survival) and the 5-year DFS (disease free survival) for the high M/C ratio group were significantly higher than those of the low M/C ratio group (41.0% vs. 6.7%, P = 0.000; 44.1% vs. 24.9%, P = 0.007). Both the M/C ratio of p120(ctn) and N status were independent variables for the prediction of overall survival (P = 0.007 and P = 0.027). The M/C of p120(ctn) predicted a 0.49-fold risk of ESCC death (p = 0.007, 95% CI 0.29–0.83). CONCLUSIONS: The reduced M/C ratio of p120(ctn) acted as an independent prognostic factor for ESCC patient survival and for the migration and invasive behavior of the disease.