Table 1. Clinicopathological features in relation to EGFR mutations in patients with lung cancer.

Variables	Category	n	EGFR mutation (%)		Exon 19 deletion	Exon 21 L858R
Gender	Male	302	62a	20.5%	34	29
	Female	167	76	45.5%	28	48
Histology	Adenocarcinoma	322	136a	42.2%	62	75
	Squamous cell ca.	102	0	0.0%
	Large cell ca.	27	1	3.7%		1
	Small cell ca.	13	0	0.0%
	Pleomorphic ca.	2	1	50.0%		1
	Adenosquamous ca.	1	0	0.0%
	Carcinoid tumour	1	0	0.0%
	Spindle cell ca.	1	0	0.0%
Smoking	Never	138	74a	53.6%	29	46
	Formerb	114	31	27.2%	18	13
	Current	217	33	15.2%	15	18
	Total	469	138a	29.4%	62	77

^aOne case had mutations in both exons 19 and 21.

^bFormer smokers are defined persons who stopped smoking more than 3 years previously.