We also found that PTEN expression was down-regulated in NSCLC that had lymph node or distal metastasis compared with those had not spread (Figure 6B), and the expression of PTEN was significantly decreased in lung cancer with advanced (stage III and IV, n = 37) to early stages (stage I and II, n = 36) (Supplementary Figure S3 A and B). Here, PTEN is linked to lung cancer.