PTEN and non-small cell lung carcinoma: Taken together, we have not observed any change in the levels of miR-21 and its target genes both in YTMLC-90 and NCI-H157 cells suggesting that similar regulatory mechanisms of between miR-21 and its target genes (PTEN, RECK and Bcl-2) involved in cell proliferation, viability, invasion, migration and apoptosis occur in GSQCLC as well as NSCLC.