CYP2E1 PstI/RsaI polymorphism and colorectal cancer risk: A meta-analysis

Table 1 Main characteristics of studies included in this meta-analysis

Author, yr	Ethnicity (country)	Source of controls	Matching criteria	Sample size (case/control)	Genotype (case/controls)			HWE
					c1c1	c2c2	c1c2 + c2c2
Butler et al[9], 2001	Caucasian (Australian)	Population-based	Age, sex	219/200	147/194	NA/NA	2/6	NA
Le Marchand et al[10], 2002	Mixed (Japanese, Caucasian, Hawaiian)	Population-based	Age, sex, ethnicity	521/639	384/449	21/26	137/190	No1
Yu et al[11], 2004	Asian (Chinese )	Population-based	Cancer-free	126/343	69/209	3/8	57/129	Yes
Landi et al[12], 2005	Caucasian (Spanish)	Hospital-based	Cancer-free	377/326	323/283	1/1	18/16	Yes
van der Logt et al[13], 2006	Caucasian (Netherlander)	Population-based	Age > 18-yr, without (family) history of CRC	371/415	333/389	1/2	24/23	Yes
Kiss et al[14], 2007	Caucasian (Hungarian)	Both	Age, sex, red meat intake, smoking	500/500	428/456	7/2	72/44	Yes
Küry et al[15], 2007	Caucasian (French)	Population-based	Age, sex	1023/1121	940/1027	6/1	73/91	Yes
Gao et al[16], 2007	Asian (Chinese )	Population-based	Age, sex, ethnicity	315/439	185/266	22/13	128/167	Yes
Cotterchio et al[17], 2008	Caucasian (Canadian )	Population-based	Age, sex	842/1251	784/1162	0/0	48/85	Yes
Morita et al[18], 2009	Asian (Japanese )	Population-based	Sex, smoking, red meat intake, residence area	685/778	412/455	36/44	273/323	Yes

¹The deviation from HWE was allowed in mixed control populations. HWE: Hardy-Weinberg equilibrium; NA: Not available.

Table 2 Results of meta-analysis for CYP2E1 PstI/RsaI polymorphism and colorectal cancer risk

Analysis	Number of cases/controls	c1c2 + c2c2 vs c1c1		c2c2 vs c1c1
		OR (95% CI)	P/Ph	OR (95% CI)	P/Ph
Overall	4979/6012	1.02 (0.88, 1.19)	0.780/0.094	1.24 (0.93, 1.66)	0.148/0.148
Subgroup analysis for ethnicity
Asian	1126/1560	1.03 (0.88, 1.21)	0.707/0.274	1.35 (0.66, 2.75)	0.414/0.072
Caucasian	3332/3813	1.05 (0.78, 1.41)	0.747/0.066	2.67 (1.03, 6.89)	0.043/0.389
Mixed	521/639	0.84 (0.65, 1.09)	0.196/NA	0.94 (0.52, 1.71)	0.850/NA
Subgroup analysis for tumor location
Colon cancer	907/2188	1.09 (0.83, 1.43)	0.522/0.082	1.22 (0.85, 1.77)	0.279/0.809
Rectum cancer	739/2188	0.89 (0.75, 1.06)	0.206/0.241	0.97 (0.38, 2.43)	0.941/0.014

P_h: P values for heterogeneity from Q test.