GST polymorphisms are associated with hepatocellular carcinoma risk in Chinese population

Table 1 Characteristics of studies included in the meta-analysis of GSTM1

Ref.	Language of publication	Residence area of subjects	Case			Control			Source of control	OR (95% CI)	Earlier or smaller reports
			Null	Positive	Total	Null	Positive	Total
Dong et al[28], 1997	Chinese	Jiangsu, Guangxi and Hebei	62	48	110	50	62	112	Population	1.602 (0.943-2.721)	[29,30]
Yu et al[31], 1999	English	Taiwan	42	42	84	216	159	375	Hospital	0.736 (0.458-1.183)	[32-37]
Wu et al[38], 2000	Chinese	Hu’nan	38	16	54	62	74	136	Population	2.835 (1.444-5.565)	NA
Sun et al[39], 2001	English	Taiwan	26	43	69	77	51	128	Population	0.400 (0.219-0.731)	NA
Zhu et al[40], 2001	Chinese	Guangdong	34	18	52	41	59	100	Hospital	2.718 (1.354-5.455)	NA
Chen et al[41], 2002	English	Taiwan	60	41	101	19	16	35	Hospital	1.232 (0.568-2.674)	NA
Liu et al[42], 2002	Chinese	Jiangsu	56	28	84	69	75	144	Population	2.174 (1.243-3.803)	[43-46]
McGlynn et al[47], 2003	English	Jiangsu	NA	NA	231	NA	NA	256	Population	0.830 (0.570-1.210)	[48-50]
Li et al[51], 2004	Chinese	Jiangsu	122	85	207	118	89	207	Population	1.083 (0.733-1.600)	NA
Chen et al[52], 2005	English	Taiwan	322	255	577	231	158	389	Population	0.864 (0.666-1.121)	[53]
Deng et al[54], 2005	English	Guangxi	117	64	181	172	188	360	Hospital	1.998 (1.383-2.888)	[55-58]
Guo et al[59], 2005	Chinese	Henan	67	28	95	52	51	103	Population	2.347 (1.306-4.218)	NA
He et al[60], 2005	Chinese	Guangxi	68	37	105	77	74	151	Hospital	1.766 (1.059-2.947)	[61,62]
Long et al[63], 2005	Chinese	Guangxi	92	48	140	254	282	536	Hospital	2.128 (1.444-3.137)	[64]
Ma et al[65], 2005	Chinese	Guangxi	37	25	62	29	44	73	Population	2.246 (1.125-4.481)	NA
Zhang et al[66], 2005	Chinese	Hubei	37	23	60	28	45	73	Hospital	2.585 (1.281-5.219)	NA
Zhu et al[67], 2005	Chinese	Zhejiang	56	35	91	61	69	130	Hospital	1.810 (1.049-3.121)	NA
Long et al[68], 2006	English	Guangxi	179	78	257	312	337	649	Hospital	2.479 (1.823-3.370)	NA
Yang et al[69], 2009	Chinese	Guangxi	59	41	100	41	19	60	Hospital	0.667 (0.340-1.309)	NA

NA: Not available; OR: Odds ratio.

Table 2 Characteristics of studies included in the meta-analysis of GSTT1

Ref.	Language of publication	Residence area of subjects	Case			Control			Source of control	OR (95% CI)	Earlier or smaller reports
			Null	Positive	Total	Null	Positive	Total
Dong et al[28], 1997	Chinese	Jiangsu, Guangxi and Hebei	63	47	110	42	70	112	Population	2.234 (1.305-3.825)	[29,30]
Yu et al[31], 1999	English	Taiwan	41	42	83	181	194	375	Hospital	1.046 (0.650-1.683)	[32-37]
Sun et al[39], 2001	English	Taiwan	30	37	67	77	51	128	Population	0.537 (0.295-0.976)	NA
Liu et al[42], 2002	Chinese	Jiangsu	34	50	84	36	108	144	Population	2.040 (1.146-3.630)	[43-46]
McGlynn et al[47], 2003	English	Jiangsu	NA	NA	231	NA	NA	256	Population	0.880 (0.590-1.310)	[48-50]
Liu et al[70], 2003	Chinese	Guangxi	28	23	51	18	35	53	Population	2.367 (1.072-5.227)	NA
Li et al[51], 2004	Chinese	Jiangsu	108	99	207	97	110	207	Population	1.237 (0.841-1.820)	NA
Chen et al[52], 2005	English	Taiwan	298	279	577	199	190	389	Population	1.020 (0.788-1.319)	[53]
Deng et al[54], 2005	English	Guangxi	108	73	181	154	206	360	Hospital	1.979 (1.377-2.845)	[55-58]
Guo et al[59], 2005	Chinese	Henan	58	37	95	45	58	103	Population	2.020 (1.146-3.562)	NA
He et al[60], 2005	Chinese	Guangxi	43	62	105	50	101	151	Hospital	1.401 (0.836-2.347)	[61,62]
Long et al[63], 2005	Chinese	Guangxi	82	58	140	234	302	536	Hospital	1.825 (1.251-2.660)	[64]
Ma et al[65], 2005	Chinese	Guangxi	35	27	62	21	52	73	Population	3.210 (1.573-6.551)	NA
Zhang et al[66], 2005	Chinese	Hubei	38	22	60	34	39	73	Hospital	1.981 (0.986-3.982)	NA
Long et al[68], 2006	English	Guangxi	146	111	257	297	352	649	Hospital	1.559 (1.165-2.086)	NA
Yang et al[69], 2009	Chinese	Guangxi	33	67	100	11	49	60	Hospital	2.194 (1.010-4.765)	NA

NA: Not available; OR: Odds ratio.

Table 3 Subgroup analysis of the association between GSTM1 polymorphism and hepatocellular carcinoma risk

Group	No. of studies (cases/controls)	Statistical method	OR (95% CI)	P
All studies	19 (2660/4017)	Random	1.487 (1.159-1.908)	0.002
Residence area of the subjects
High-incidence area	11 (1510/2666)	Random	1.659 (1.264-2.177)	0.000
Low-incidence area	7 (1040/1239)	Random	1.235 (0.753-2.026)	0.402
Mixed areas	1 (110/112)	-	1.602 (0.943-2.721)	0.081
No. of cases
< 100	9 (651/1262)	Random	1.676 (1.061-2.649)	0.027
≥ 100	10 (2009/2755)	Random	1.365 (1.005-1.853)	0.046
Source of controls
Population-based	9 (1489/1548)	Random	1.316 (0.915-1.892)	0.139
Hospital-based	10 (1171/2469)	Random	1.675 (1.251-2.243)	0.001

OR: Odds ratio.

Table 4 Subgroup analysis of the association between GSTT1 polymorphism and hepatocellular carcinoma risk

Group	No. of studies (cases/controls)	Statistical method	OR (95% CI)	P
All studies	16 (2410/3669)	Random	1.510 (1.236-1.845)	0.000
Residence area of the subjects
High-incidence area	10 (1418/2489)	Random	1.641 (1.328-2.027)	0.000
Low-incidence area	5 (882/1068)	Random	1.152 (0.777-1.707)	0.483
Mixed areas	1 (110/112)	-	2.234 (1.305-3.825)	0.003
Number of cases
< 100	7 (502/949)	Random	1.617 (1.035-2.528)	0.035
≥ 100	9 (1908/2720)	Random	1.457 (1.173-1.810)	0.001
Source of controls
Population-based	9 (1484/1465)	Random	1.441 (1.039-1.997)	0.028
Hospital-based	7 (926/2204)	Fixed	1.635 (1.391-1.921)	0.000

OR: Odds ratio.