Expression and prognostic significance of PTEN product protein in patients with esophageal squamous cell carcinoma

BACKGROUND. PTEN is a candidate tumor-suppressor gene in a variety of malignant tumors. The prognostic importance of PTEN product protein (PTEN) and its correlation with clinicopathologic characteristics have yet to be delineated in patients with esophageal carcinoma. METHODS. Specimens from 97 patients with esophageal squamous cell carcinoma were used for the immunohistochemical evaluation of PTEN expression. RESULTS. PTEN expression was detected in the nucleus in 48 specimens (49.5%). There were statistically significant correlations between nuclear PTEN expression and macroscopic tumor classification, T stage, and American Joint Committee on Cancer (AJCC) stage (P < 0.01), indicating that PTEN expression was down-regulated by advancement of the disease process. There were no statistically significant correlations between nuclear PTEN expression and the intensity and extent of cytoplasmic PTEN expression. The 10-year overall survival rate was significantly better in patients with positive nuclear PTEN expression (n = 48 patients) compared with the rate in patients with negative nuclear PTEN expression (n = 49 patients; P < 0.01). The results of a multivariate analysis of factors that were prognostic for survival showed that AJCC stage (P < 0.05; relative risk, 2.038) and negative nuclear PTEN expression (P < 0.05; relative risk, 1.825) were significant factors indicative of poor survival. CONCLUSIONS. Nuclear PTEN expression may be a favorable biologic marker and a useful prognostic indicator in patients with esophageal squamous cell carcinoma.