Combined effects of cigarette smoking, gene polymorphisms and methylations of tumor suppressor genes on non small cell lung cancer: a hospital-based case-control study in China

Table 5 The interactions between cigarette smoking, genetic variants of CYP1A1and GSTM1, and promoter hypermethylations of the p16, DAPK and RARβ genes in non-small cell lung cancer

Factor	OR ^a (95% CI)
	Cases with TSG^b promoter hypermethylation			Cases without TSG promoter hypermethylation
	p16	DAPK	RARβ	p16	DAPK	RARβ
Smoking habit (yes/no)	4.56**	3.83**	3.11**	1.34	1.23	1.45
	(2.17-9.58)	(1.99-7.38)	(1.67-5.78)	(0.76-2.37)	(0.67-2.26)	(0.77-2.71)
Pack years
<20	1.00	1.00	1.00	1.00	1.00	1.00
	(reference)	(reference)	(reference)	(reference)	(reference)	(reference)
20-29	4.62**	6.72**	3.27*	2.60	1.23	3.27*
	(1.63-13.13)	(2.63-17.18)	(1.23-8.69)	(0.99-6.80)	(0.37-4.12)	(1.19-9.01)
30-39	5.08**	6.82**	4.27**	1.75*	1.58	2.70*
	(2.04-12.69)	(2.2.94-15.81)	(1.88-9.70)	(1.19-6.36)	(0.59-4.20)	(1.06-6.89)
≥40	14.29**	13.50**	9.50**	4.17**	4.01**	5.34**
	(6.55-31.18)	(6.31-28.89)	(4.62-19.53)	(1.96-8.88)	(1.85-8.68)	(2.40-11.88)
x ²test for trend	p < 0.001	p < 0.001	p < 0.001	p < 0.001	p < 0.001	p < 0.001
CYP1A1 ((Aa+aa)/AA) ^c	0.97	1.14	1.06	1.07	0.88	0.94
	(0.55-1.81)	(0.67-1.92)	(0.62-1.80)	(0.61-1.86)	(0.48-1.59)	(0.51-1.71)
GSTM1 (null/power) ^d	1.45	1.73*	1.98**	1.67	1.33	1.10
	(0.82-2.56)	(1.01-2.99)	(1.15-3.44)	(0.96-2.94)	(0.73-2.43)	(0.60-2.00)

^a adjusted for sex, age, alcohol habit, tea habit, smoking habit and history of lung cancer in first-degree relatives.
^b TSG = tumor suppress gene including p16, DAPK and RARβ.
^c AA = homogeneity wild genotype, Aa = heterogeneity genotype, aa = homogeneity variant genotype
^d - = null type, + = power
* p < 0.05, **p < 0.01

ISSN: 1471-2407