Increased ZO-1 expression predicts valuable prognosis in non-small cell lung cancer

Objective: The aim of this study was to investigate the expression of Zonula Occludens-1 (ZO-1) and its potential value as prognostic indicator of survival in patients with primary non-small cell lung cancer (NSCLC). Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry with tissue microarrays were used to characterize the expression of the ZO-1 mRNA and protein in NSCLC. The correlation of ZO-1 expression with clinical characteristics and prognosis was determined by statistical analysis. Results: The ZO-1 mRNA and protein levels were significantly lower in NSCLC tissue compared with corresponding peritumoral tissue (P<0.05). ZO-1 protein expression in NSCLC was related to age (P=0.042) and 5-year survival (P<0.001). Kaplan-Meier survival and Cox regression analyses revealed that low ZO-1 expression (P<0.001) and later stage grouping by TNM (P=0.031) were independent factors predicting poor prognosis for patients with NSCLC. Conclusions: Our findings provide the first evidence that high expression of ZO-1 is associated with good prognosis in NSCLC.