RNA interference (RNAi) has been shown to be an effective method for inhibiting the expression of a given gene in human cells by targeting with short duplex RNA (short-interfering RNA or siRNA). However, more and more studies suggest that non-specific effects can be induced by siRNAs, such as off-target inhibition, activation of interferon response, and saturation of cellular silencing machinery. It has been known that more than 90% of human tumors exhibit teiomerase activity. Consequently, teiomerase is believed to be a broadspectrum molecular marker of malignancies. In the present study we attempt to develop a tumor-specific RNAi system using the human telomerase reverse transcriptase promoter.This system may provide a basis for RNAi therapy.