Table 1. The characteristics of the patients.

	Lung cancer	Benign group	P value
Age, years	60.8 ± 1.2	58.2 ± 1.7	0.20
Gender			0.68
Male	28	19
Female	17	14
Smoking status			0.55
Smokers	20	12
Non-smokers	25	21
Pack/years	66.1 ± 9.3	29.6 ± 5.3	0.001
Histological type
Squamous cell carcinoma	18
Adenocarcinoma	11
Small-cell lung cancer	10
Others	6