Table 3. FOXP3 mRNA expression levels in the six study groups.

Group	Healthy	Lung cancer	P
Young (18–44 years)	1.17 ± 0.51	2.28 ± 1.21	<0.01
Middle-aged (45–59 years)	1.76 ± 0.80a	2.53 ± 1.16c
Elderly (60–90 years)	2.67 ± 0.99b	3.14 ± 1.30d

The expression level of FOXP3 mRNA in the peripheral blood was considerably higher in patients than in controls by student’s t test (P < 0.01). FOXP3 mRNA levels also increased with age according to one-way analysis of variance:

^a P < 0.01 compared with the young healthy group,

^b P < 0.01 compared with the middle-aged healthy group,

^c P < 0.01 compared with the young lung cancer group,

^d P < 0.01 compared with the middle-aged lung cancer group.