Down-regulation of Dicer in hepatocellular carcinoma.

Dicer, the key enzyme in the RNAi pathway, is misregulated in tumor tissues. The altered expression of Dicer is associated with clinical characteristics in patients with cancer. Liver carcinoma and adjacent non-neoplastic tissues were obtained from 36 patients with hepatocellular carcinoma (HCC) undergoing surgery. Expressions of Dicer mRNA were evaluated using the Real-time reverse transcription-PCR in 36 liver carcinoma tissues and 36 adjacent histologically non-cancerous liver tissues. Dicer mRNA levels were evaluated in relation to age, sex, tumor number, tumor size, tumor stage, and distant metastasis. Dicer mRNA level was significantly lower in malignant tissues than in the corresponding non-neoplastic tissues in 34 of the 36 patients with HCC (94.4%). The Dicer expression level was not associated with clinical characteristics, including age, sex, tumor number, tumor size, tumor stage, or distant metastasis in HCC cases. These results demonstrate that Dicer is significantly down-regulated in HCC, suggesting that reduced expression of Dicer may play an important role during the process of hepatocarcinogenesis.