Decreased expression of claudin-1 is correlated with recurrence status in esophageal squamous cell carcinoma.

Claudins are transmembrane proteins and major constitutes of tight junctions, and participate in the paracellular barrior and cellular connecting functions. They have been shown to be differentially regulated in malignant tumors and play a role in carcinogenesis and tumor progression. Recent studies have shown changes in expression of claudins during tumorigenesis. However, a causal relationship between claudin expression and cancer recurrent status has not been established. In this study, we examined 54 esophageal cancer cases to assess immunohistochemical expression patterns of claudin-1. Eleven (20.4%) of 54 cases had negative immunostaining for claudin-1. Decreased expression of claudin-1 was statistically correlated with recurrence status (P = 0.018). The cases with lymphatic vessel permeation showed reduced expression patterns of claudin-1 (P = 0.033). Decreased expression of claudin-1 was also correlated with short diseasefree survival (P = 0.0003) and overall survival (P = 0.0045). The results indicated that claudin-1 expression was correlated with the recurrence status and poor prognosis in esophageal cancer and claudin-1 expression may be a good indicator of recurrence in esophageal cancer.