AXL and small cell lung carcinoma: In addition, amplification of the MET gene has been reported to contribute to resistance in approximately 5–20% of cases [6-8] and increased AXL expression was recently discovered to occur in almost 20% of patients [9] phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA) mutation, epithelial-to-mesenchymal transition (EMT) and small cell lung cancer (SCLC) transformation are also associated with acquired resistance [6].