EGFR and squamous cell carcinoma: With regards to the EGFR mutations in the different histological subtypes, this study showed that the highest EGFR-TKIs sensitive mutation frequency occurred in adenocarcinoma (41.8% (493/1178)) and this was followed by adenosquamous carcinoma, (30.9% (21/68)), squamous cell carcinoma (6.6% (12/181)) and others (6.1% (11/79)).