ALK and lung cancer: For example, in 2007 a global survey of phosphotyrosine signaling in non‐small cell lung cancer (NSCLC) cell lines and tumors revealed unusually high activities of ALK and proto‐oncogene tyrosine‐protein kinase ROS (ROS).84 Follow‐up western blotting, RT‐PCR, and DNA sequencing in these samples revealed oncogenic ALK and ROS fusion proteins, including the fusion of ALK to echinoderm microtubule‐associated protein‐like 4 (EML4).