Overexpression of various microRNAs, such as miR-21, miR-221, and miR-222,38,39 as well as methylation of PTEN promoter and homogenous deletion of PTEN gene, are the most significant mechanisms for reducing PTEN activity in lung cancer.40 Therefore, different pathways correlate with the hyperactivation of Akt signaling and the growth and progression of lung cancer cells. This evidence concerns the gene PTEN and lung cancer.