Association between esophageal cancer risk and EPHX1 polymorphisms: A meta-analysis

Table 1 Characteristics of the studies included in the meta-analysis

Study	Year	Country	Ethnicity	Cases	Controls	Source of controls	Type of cancer	DNA source
Dura et al[9]	2012	The Netherlands	Caucasian	349	581	PB	ESCC and EADC	Blood and tissue samples
Ihsan et al[10]	2010	India	Asian	142	185	PB	ESCC	Blood samples
Jain et al[11]	2008	India	Asian	107	320	PB	ESCC	Blood samples
Casson et al[16]	2006	Canada	Caucasian	56	95	HB	EADC	Blood samples
Lin et al[13]	2006	China	Asian	145	352	PB	ESCC	Blood samples
Zhang et al[14]	2003	China	Asian	257	252	HB	ESCC	Blood samples
Wang et al[15]	2003	China	Asian	62	38	PB	ESCC	Tissue samples

EPHX1: Microsomal epoxide hydrolase; ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; PB: Population-based controls; HB: Hospital-based controls.

Table 2 Distribution of epoxide hydrolase p.Tyr113His genotypes in controls and esophageal cancer patients

Variable	Studies	Cases/controls	OR (95%CI)	P value	P for heterogeneity	I2	Model
Tyr/His vs Tyr/Tyr
Total	7	1118/1823	1.00 (0.70-1.48)	0.928	0.001	72.8	R
Caucasian	2	405/676	0.92 (0.71-1.20)	0.555	0.192	41.2	F
Asian	5	713/1147	1.14 (0.65-2.00)	0.638	0.001	79.9	R
ESCC	6	804/1147	1.08 (0.69-1.69)	0.746	0.001	75.6	R
EADC	2	314/676	0.95 (0.71-1.26)	0.729	0.160	49.2	F
PB	5	805/1476	1.04 (0.66-1.66)	0.857	0.001	78.3	R
HB	2	313/347	0.95 (0.39-2.28)	0.902	0.057	72.4	R
His/His vs Tyr/Tyr
Total	7	1118/1823	1.10 (0.77-1.57)	0.592	0.046	53.3	R
Caucasian	2	405/676	0.74 (0.48-1.13)	0.165	0.172	46.5	F
Asian	5	713/1147	1.23 (0.94-1.60)	0.137	0.120	45.3	F
ESCC	6	804/1147	1.18 (0.92-1.52)	0.196	0.158	37.2	F
EADC	2	314/676	0.72 (0.45-1.15)	0.163	0.183	43.7	F
PB	5	805/1476	1.18 (0.78-1.78)	0.423	0.079	52.1	R
HB	2	313/347	0.78 (0.24-2.58)	0.688	0.034	77.7	R
His/His + Tyr/His vs Tyr/Tyr
Total	7	1118/1823	1.06 (0.75-1.49)	0.753	0.001	74.0	R
Caucasian	2	405/676	0.76 (0.42-1.38)	0.367	0.088	65.6	R
Asian	5	713/1147	1.23 (0.77-1.98)	0.382	0.001	77.8	R
ESCC	6	804/1147	1.15 (0.78-1.70)	0.484	0.002	74.0	R
EADC	2	314/676	0.77 (0.41-1.46)	0.421	0.074	68.6	R
PB	5	805/1476	1.13 (0.74-1.70)	0.575	0.002	77.0	R
HB	2	313/347	0.87 (0.33-2.26)	0.769	0.017	82.4	R
His/His vs Tyr/His + Tyr/Tyr
Total	7	1118/1823	1.09 (0.89-1.34)	0.416	0.188	31.4	F
Caucasian	2	405/676	0.77 (0.51-1.16)	0.213	0.281	13.9	F
Asian	5	713/1147	1.23 (0.97-1.55)	0.093	0.388	3.3	F
ESCC	6	804/1147	1.20 (0.95-1.50)	0.121	0.469	0.0	F
EADC	2	314/676	0.91 (0.29-2.84)	0.878	0.041	76.1	R
PB	5	805/1476	1.14 (0.89-1.45)	0.294	0.210	31.8	F
HB	2	313/347	0.97 (0.66-1.43)	0.888	0.111	60.6	F

EPHX1: Microsomal epoxide hydrolase; OR: Odds ratio; R: Random-effects model; F: Fixed-effects model; ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; PB: Population-based controls; HB: Hospital-based controls.

Table 3 Distribution of the microsomal epoxide hydrolase p.His139Arg genotypes in controls and esophageal cancer patients

Variable	Studies	Cases/controls	OR (95%CI)	P value	P for heterogeneity	I2	Model
Arg/His vs His/His
Total	6	861/1571	1.02 (0.84-1.23)	0.869	0.176	34.8	F
Caucasian	2	405/676	0.97 (0.74-1.27)	0.824	0.955	0.0	F
Asian	4	456/895	1.09 (0.69-1.73)	0.709	0.060	59.4	R
ESCC	5	547/1319	0.99 (0.67-1.46)	0.954	0.052	57.5	R
EADC	2	314/676	1.05 (0.79-1.40)	0.718	0.755	0.0	F
PB	5	805/1476	1.02 (0.84-1.24)	0.833	0.106	47.5	F
HB	1	56/95	0.95 (0.47-1.91)	NA	NA	NA	NA
Arg/Arg vs His/His
Total	6	861/1571	0.96 (0.60-1.54)	0.855	0.206	30.6	F
Caucasian	2	405/676	0.61 (0.31-1.21)	0.158	0.308	3.9	F
Asian	4	456/895	1.59 (0.80-3.16)	0.184	0.324	13.6	F
ESCC	5	547/1319	1.28 (0.72-2.30)	0.402	0.346	10.6	F
EADC	2	314/676	0.60 (0.28-1.27)	0.178	0.313	1.8	F
PB	5	805/1476	1.08 (0.66-1.76)	0.765	0.251	25.5	F
HB	1	56/95	0.22 (0.03-1.90)	NA	NA	NA	NA
Arg/Arg + Arg/His vs His/His
Total	6	861/1571	1.03 (0.78-1.37)	0.810	0.095	46.6	R
Caucasian	2	405/676	0.92 (0.71-1.20)	0.555	0.719	0.0	F
Asian	4	456/895	1.14 (0.71-1.81)	0.593	0.042	63.5	R
ESCC	5	547/1319	1.02 (0.68-1.53)	0.918	0.028	63.1	R
EADC	2	314/676	1.00 (0.75-1.31)	0.976	0.550	0.0	F
PB	5	805/1476	1.07 (0.78-1.48)	0.676	0.062	55.5	R
HB	1	56/95	0.82 (0.42-1.62)	NA	NA	NA	NA
Arg/Arg vs Arg/His + His/His
Total	6	861/1571	0.97 (0.61-1.56)	0.911	0.247	25.0	F
Caucasian	2	405/676	0.62 (0.31-1.21)	0.163	0.307	4.0	F
Asian	4	456/895	1.66 (0.84-3.30)	0.148	0.454	0.0	F
ESCC	5	547/1319	1.36 (0.76-2.45)	0.297	0.480	0.0	F
EADC	2	314/676	0.58 (0.28-1.24)	0.160	0.328	0.0	F
PB	5	805/1476	1.10 (0.67-1.80)	0.704	0.312	16.1	F
HB	1	56/95	0.23 (0.03-1.91)	NA	NA	NA	NA

EPHX1: Microsomal epoxide hydrolase; OR: Odds ratio; R: Random-effects model; F: Fixed-effects model; ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; PB: Population-based controls; HB: Hospital-based controls; NA: Not available.