Anaplastic Lymphoma Kinase (ALK) Signaling in Lung Cancer

Chromosomal rearrangement in the anaplastic lymphoma kinase (ALK) gene was identified as an oncogenic driver in non-small cell lung cancer (NSCLC) in 2007. A multi-targeted ALK/ROS1/MET inhibitor, crizotinib, targeting this activated tyrosine kinase has led to significant clinical benefit including tumor shrinkage and prolonged survival without disease progression and has been approved by US FDA since 2011 for the treatment of advanced ALK- rearranged NSCLC (Ou et al. Oncologist 17:1351-1375, 2012). Knowledge gained from treating ALK-rearranged NSCLC patients including the presenting clinicopathologic characteristics, methods of detecting ALK-rearranged NSCLC, pattern of relapse and acquired resistance mechanisms while on crizotinib, and the clinical activities of more potent ALK inhibitors has led us to a detailed and ever expanding knowledge of the ALK signaling pathway in lung cancer but also raising many more questions that remained to be answered in the future. This book chapter will provide a concise summary of the importance of ALK signaling pathway in lung cancer. Understanding the ALK signaling pathway in lung cancer will likely provide the roadmap to the management of major epithelial malignancies driven by receptor tyrosine kinase rearrangement.