Overexpression of metallothionein correlates with chemoresistance to cisplatin and prognosis in esophageal cancer.

The aim of this study was to determine the correlation of metallothionein (MT) expression with resistance to cisplatin and to identify prognostic factors in esophageal cancer. Immunostaining for MT was performed on the specimens of squamous cell carcinoma of the esophagus resected from 68 patients with curative intent. The expression of MT was evaluated in terms of clinicopathologic variables, effect of cisplatin, and the patients' survival. Overexpression of MT in the tumor was found in 70.6% of the patients. Stage III and IV tumors were more common in MT-positive tumors (p = 0.0282) but there was no difference in other clinicopathologic variables between MT-positive and MT-negative groups. Stage, cisplatin therapy, and tumor length were the independent prognostic indicators by multivariate analysis. Among 43 patients treated with cisplatin, the 5-year survival rate was 56% for MT-negative and 26% for MT-positive patients (p = 0.0277). In the MT-negative patients, multivariate analysis revealed that curability, stage, cisplatin therapy, and tumor length were the independent prognostic factors. These findings suggest that MT expression in squamous cell carcinoma of the esophagus is a major determinant of the chemoresistance to cisplatin and may be a predictor of poor prognosis.