Expression of Minichromosome Maintenance Protein 7 and Smad 4 in Squamous Cell Carcinoma of the Esophagus

ABSTRACT

BACKGROUND: Minichromosome maintenance protein 7 (MCM 7) performs a direct role in the initiation of DNA replication, which suggests that it may prove useful as a marker of cell proliferation. Smad 4 is a tumor suppressor gene that mediates the transforming growth factor beta pathway. The principal objective of this study was to characterize the expression of MCM 7 and Smad 4 and to analyze their relationship to clinicopathological parameters in patients with esophageal squamous cell carcinoma. METHODS: Expression levels of MCM 7 and Smad 4 were evaluated via immunohistochemistry on formalin-fixed and paraffin-embedded tissues from 67 cases of esophageal squamous cell carcinoma. RESULTS: High levels of MCM 7 expression were detected in 53 cases (74.6%), and were associated with higher T stages (p = 0.030). Kaplan-Meier survival curves demonstrated that patients with higher levels of MCM 7 expression had poorer prognoses, although this association was not significant (p = 0.086). Loss of Smad 4 expression was noted in 18 cases (23.4%), and was not associated with clinicopathological characteristics, including MCM 7 expression, or prognosis. CONCLUSIONS: MCM 7 expression is associated with the invasiveness of esophageal squamous cell carcinoma. Altered expression of Smad 4 does not appear to have pathobiological significance in esophageal carcinoma.