Table 2.

 Correlation between PTEN methylation and the clinico‐pathological features

	Methylation frequency (%)
	Region 1	Region 2	Region 3
All subjects (n = 137)	7 (5.1)	4 (2.9)	0
Age
≤63 years (n = 64)	4 (6.3)	3 (4.7)	0
>63 years (n = 73)	3 (4.1)	1 (1.4)	0
Gender
Male (n = 93)	4 (4.3)	3 (3.2)	0
Female (n = 44)	3 (6.8)	1 (2.3)	0
Smoking status
Ever (n = 96)	5 (5.2)	3 (3.1)	0
Never (n = 41)	2 (4.9)	1 (2.4)	0
Histologic types
Squamous cell carcinoma (n = 59)	2 (3.4)	2 (3.4)	0
Adenocarcinoma (n = 78)	5 (6.4)	2 (2.6)	0
Adenocarcinoma
EFGR mutation (−) (n = 60)	3 (5.0)	1 (1.7)	0
EFGR mutation (+) (n = 18)	2 (11.1)	1 (5.5)	0
Pathologic stages
Stage I (n = 86)	5 (5.8)	2 (2.3)	0
Stages II–IV (n = 51)	2 (3.9)	2 (3.9)	0

PTEN, phosphate and tension homolog.