Table 12. Mutation types and basic information of EGFR gene mutations.

Clinicopathological features	Classification	Cases	Rate (%)
Gender	Male	25	51.02
	Female	24	48.98
Age	≥60	22	44.90
	<60	27	55.10
TNM staging	IV	45	91.84
	Non-IV	4	8.16
Smoking history	Yes	22	44.90
	No	27	55.10
Pathological type	ADC	47	95.92
	SCC	2	4.08
EGFR gene mutations	Exon 2	1	1.35
	Exon 4	1	1.35
	Exon 6	1	1.35
	Exon 18	1	1.35
	Exon 19	25	33.78
	Exon 20	12	16.22
	Exon 21	19	25.68
	Exon 22	1	1.35
	EGFR amplification	13	17.57

ADC, adenocarcinoma; SCC, squamous cell carcinoma.