Human telomerase reverse transcriptase (hTERT) is the catalytic subunit and the activity determinant factor of the telomerase enzyme which maintains the length of human chromosomes. In recent years it has become an attractive molecular target for cancer gene therapy. In the present study, we show that hTERT siRNA effectively suppressed the expression of hTERT mRNA and hTERT protein levels, reduced telomerase activity, and induced apoptosis of A549 lung adenocarcinoma cells (P