To study Ras-mediated downstream phosphorylation events and Ras involvement in lung cancer, Cdk4/hTERT-immortalized human bronchial epithelial cells (HBEC3-KT or 3KT) and KRASV12-transformed 3KT (3KTR) cells were subjected to quantitative phosphoproteomics analysis. This evidence concerns the gene CDK4 and lung cancer.