EGFR and small cell lung carcinoma: The poor clinical response of lung cancer cells to EGFR-TKIs is due to the inherent and acquired resistance of NSCLC cells to these agents, which is thought to occur via several mechanisms, including PI3K mutations, T790M mutation of EGFR, MET amplification, HER-2 amplification, and transformation into a small-cell lung cancer phenotype (Antonicelli et al., 2013; Kumarakulasinghe et al., 2015).