ERK signaling is generally associated with a proliferative response (Gollob et al. 2006), but prolonged activation of the pathway mediates cell cycle arrest in cells derived from a variety of benign and malignant tissues, including lung cancer (Wen-Sheng 2006; Clark et al. 2004; Sriuranpong et al. 2001). This evidence concerns the gene MAPK1 and lung cancer.