PTEN and lung adenocarcinoma: Concordantly, it has also been demonstrated that the reduction of hTERT expression using an hTERT siRNA inhibited telomerase activity and accelerated cell apoptosis in lung cancer [35], further strengthening our hypothesis that PTEN suppresses the activity of telomerase by decreasing the expression of hTERT, leading to the inhibition of cell proliferation and the promotion cell apoptosis in lung adenocarcinoma A549 cells.