Dysregulated expression of dicer and drosha in breast cancer.

Large-scale profiling approaches have revealed global down-regulation of microRNAs (miRNAs) in several human cancer types including breast cancer. Altered expression of Dicer and Drosha, two key enzymes in the miRNA maturation, is believed to be one of the most important mechanisms. By using quantitative real-time RT-PCR (QT-PCR), we examined the expression of Dicer and Drosha in 49 pairs of matched human breast cancer tissues. Decreased expression was observed in 53.1% (Dicer), 51.9% (Drosha) and 75.5% (Dicer plus Drosha) breast cancer tissues. In conclusion, the decreased expression of Dicer and Drosha may play a role in down-regulation of miRNAs in breast cancer.