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.