CYP1A1 Ile462Val polymorphism contributes to colorectal cancer risk: A meta-analysis

Table 1 Characteristics of case-control studies included in meta-analysis

Author	Country /region	Racial descent	Source of controls	Case (n)	Control (n)	Genotype distribution						Genotying type	HWE
						Case (n)			Control (n)
						Ile/Ile	Ile/Val	Val/Val	Ile/Ile	Ile/Val	Val/Val
Sivaraman et al[10], 1994	USA	Mixed	Population control	43	47	32	9	2	33	14	0	Allele-specific PCR	0.230
Ishibe et al[18], 2000	USA	European	Population control	212	221	176	31	5	186	31	4	PCR-RFLP	0.057
Sachse et al[19], 2002	UK	European	Population control	490	592	415	68	7	539	48	5	TaqMan	< 0.01
Slattery et al[20], 2004	USA	European	Population control	997	1170	910	82	5	1077	86	7	Allele-specific PCR	< 0.01
Slattery et al[20], 2004	USA	European	Population control	794	1010	722	66	6	920	85	5	Allele-specific PCR	0.052
Landi et al[21], 2005	Italy	European	Hospital control	362	323	333	28	1	298	25	0	Microarray and APEX	0.469
Little et al[22], 2006	UK	European	Population control	251	396	235	16	0	372	24	0	PCR-RFLP	0.534
Kiss et al[13], 2007	Hungary	European	Hospital control	500	500	386	110	4	415	83	2	Allele-specific PCR	0.315
Yeh et al[23], 2007	China	Asian	Hospital control	717	729	400	228	89	410	266	53	PCR-RFLP	0.280
Yoshida et al[24], 2007	Japan	Asian	Not report	66	121	34	27	5	79	37	5	PCR-RFLP	0.800
Pereira Serafim et al[25], 2008	Brazil	Mixed	Population control	114	114	14	97	3	81	33	0	PCR-RFLP	0.071
Kobayashi et al[26], 2009	Japan	Asian	Hospital control	105	225	65	32	8	125	87	13	MassARRAY system	0.674
Nisa et al[27], 2010	Japan	Asian	Population control	685	778	418	231	36	461	276	41	PCR-RFLP	0.970

HWE: Hardy-Weinberg equilibrium in control; PCR-RFLP: Polymerase chain reaction-restriction fragment length polymorphism; APEX: Arrayed primer extension.

Table 2 Odds ratio and 95% confidence interval of CYP1A1 Ile462Val polymorphism and colorectal cancer risk

Contrast	Racial descent	OR	95% CI	Ph
Val/Val vs Ile/Ile	Total	1.47	1.16-1.86	0.44
	European	1.43	0.83-2.48	0.93
	Asian	1.40	1.07-1.82	0.23
Ile/Val vs Ile/Ile	Total	1.28	0.96-1.72	< 0.011
	European	1.22	1.05-1.42	0.25
	Asian	0.91	0.79-1.05	0.19
(Val/Val + Ile/Val) vs Ile/Ile	Total	1.33	1.01-1.75	< 0.011
	European	1.24	1.07-1.43	0.24
	Asian	0.98	0.96-1.13	0.17
Val/Val vs (Ile/Val + Ile/Ile)	Total	1.49	1.18-1.88	0.77
	European	1.39	0.80-2.41	0.94
	Asian	1.46	1.12-1.89	0.24

¹Estimates for random effects.

P_h: Test for heterogeneity; CYP1A1: Cytochrome P450, including family 1, subfamily A, polypeptide 1; OR: Odds ratio; CI: Confidence interval.