Enhanced coexpression of thioredoxin and high mobility group protein 1 genes in human hepatocellular carcinoma and the possible association with decreased sensitivity to cisplatin

Thioredoxin (TRX), a disulfide-reducing intracellular protein, functions as a cellular defense mechanism against oxidative stress. In this study, we asked whether expression of TRX, glutathione-thiol transferase π, and high mobility group protein 1 (HMG-I) genes is enhanced in human hepatocellular carcinoma and whether expression of these genes is associated with sensitivity to cisplatin. Both TRX and HMG-1 were co-overexpressed in almost all cancerous lesions in comparison to normal tissue in surgically resected hepatocellular carcinomas of 20 patients. Tumor sensitivity to cisplatin [cis-diamminedichloroplatinum (II)], but not to mitomycin C or doxorubicin, correlated with mRNA levels of TRX in cancer tissue. TRX and HMG-1 may be useful tumor markers, and TRX might he also a useful marker for sensitivity to cisplatin in human hepatocellular carcinomas.