EGFR and small cell lung carcinoma: At present, the reports of EGFR mutation-positive SCLC are still controversial, while histological transformation from non-small cell lung cancer(NSCLC) to small cell lung cancer (SCLC) has been proven to be one of the mechanisms of resistance on EGFR TKIs, occurs in 3 ~ 14% of cases [22–24], and re-biopsy sample showed original EGFR deletion mutation in SCLC components.