OVEREXPRESSION OF METALLOTHIONEIN CORRELATES WITH CHEMORESISTANCE TO CISPLATIN AND PROGNOSIS IN ESOPHAGEAL CANCER

The aim of this study was to determine the correlation of metallothion ein (MT) expression with resistance to cisplatin and to identify progn ostic factors in esophageal cancer. Immunostaining for MT was performe d on the specimens of squamous cell carcinoma of the esophagus resecte d from 68 patients with curative intent. The expression of MT was eval uated in terms of clinicopathologic variables, effect of cisplatin, an d 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 c linicopathologic variables between MT-positive and MT-negative groups. Stage, cisplatin therapy, and tumor length were the independent progn ostic indicators by multivariate analysis. Among 43 patients treated w ith 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 thera py, and tumor length were the independent prognostic factors. These fi ndings suggest that MT expression in squamous cell carcinoma of the es ophagus is a major determinant of the chemoresistance to cisplatin and may be a predictor of poor prognosis.