Many acquired resistance mechanisms and candidates have been reported so far, such as EGFR T790M secondary mutation, MET gene amplification, ERBB2 gene amplification, overexpression of hepatocyte growth factor, downregulation of PTEN, transformation to small cell lung cancer (SCLC), and epithelial to mesenchymal transition3, 4. The gene discussed is EGFR; the disease is small cell lung carcinoma.