Table 1. The clinical characteristics of the 100 patients and 60 cases of healthy volunteers.

clinical characteristics	Case of patients(%)	healthy volunteer	X2	P
Age
Median	59	57		0.432
Range	36–84	31–82
Gender
Male	80(80%)	44(73%)	0.361	0.665
Female	20(20%)	16(27%)
Pathological type
Adenocarcinoma	40(40%)
Squamous cell carcinomas	50(50%)
Others	10(10%)
Tumor differentiation grade
Poorly differentiated	44(44%)
Middle differentiated	55(55%)
High differentiated	1(1%)
pTNM stage
Ia stage	20(20%)
Ib stage	23(23%)
IIa stage	19(19%)
IIb stage	8(8%)
IIIa stage	30(30%)
N stage
N0	64(64%)
N1	9(9%)
N2	27(27%)
Smoking
Yes	59(59%)
No	41(41%)