Globally, these can be categorized as target gene alterations (i.e., EGFR amplifications and mutations such as T790M), downstream bypass signaling pathway activation (i.e., MET and HER2 amplifications or mutations in BRAF, PIK3CA), and phenotypic changes (including small-cell lung cancer transformation and epithelial to mesenchymal transition) (26, 27). The gene discussed is EGFR; the disease is small cell lung carcinoma.