According to various studies, there is an important linkage between PI3K/Akt and Ras signaling.34 K-ras mutation is responsible for 25% of smoking-associated human lung adenocarcinomas and boosts motility and invasiveness of lung adenocarcinoma cells through Akt activation.35 PTEN is a lipid phosphatase that can negatively regulate the PI3K/Akt pathway via PIP3 dephosphorylation at the plasma membrane.36 When this phosphatase is mutated, it cannot convert PI3P into PIP and the PI3K/Akt signaling pathway will be hyperactive. This evidence concerns the gene PTEN and lung adenocarcinoma.