Other molecular mechanisms for EGFR-TKI resistance include hepatocyte growth factor receptor (c-MET) amplification [11], erbb2 receptor tyrosine kinase 2 (HER2) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutation [12], BCL2-like 11 (BIM) polymorphism [13], and transformation to small cell lung cancer [14]. The gene discussed is PIK3CA; the disease is small cell lung carcinoma.