TNF-α-308 polymorphism and risk of digestive system cancers: A meta-analysis

Table 1 Characteristics of studies included in the meta-analysis

Ref.	Year	Country	Ethnicity	Cancer type	Genotyping method	Case				Control				P
						Total	GG	GA	AA	Total	GG	GA	AA
Burada et al[6]	2012	Romania	Caucasian	Gastric	TaqMan	105	78	26	1	242	196	44	2	0.78
Canedo et al[7]	2008	Portugal	Caucasian	Gastric	TaqMan	508	330	1781		713	544	1691		NA
Crusius et al[8]	2008	Spain	Caucasian	Gastric	Real-time PCR	236	170	64	2	1125	820	274	31	0.17
El-Omar et al[9]	2003	United States	Caucasian	Gastric	TaqMan	314	201	87	26	210	152	52	6	0.55
Guo et al[13]	2005	China	Asian	Gastric	PCR-RFLP	264	240	20	4	437	391	40	6	< 0.01
Jang et al[14]	2001	South Korea	Asian	Gastric	PCR-RFLP	52	46	4	2	92	85	7	0	0.70
Fei et al[15]	2004	China	Asian	Gastric	PCR	56	53	3	0	164	143	20	1	0.74
Garcia-Gonzalez et al[16]	2007	Spain	Caucasian	Gastric	TaqMan	404	309	84	11	404	320	77	7	0.35
Garza-Gonzalez et al[17]	2005	Mexico	Caucasian	Gastric	PCR-RFLP	63	0	8	55	215	1	35	179	0.61
Glas et al[18]	2004	Germany	Caucasian	Gastric	PCR-RFLP	88	66	19	3	145	105	36	4	0.67
Hou et al[19]	2007	Poland	Caucasian	Gastric	TaqMan	305	186	98	21	428	304	109	15	0.19
Kamangar et al[20]	2006	Finland	Caucasian	Gastric	TaqMan	112	86	23	3	208	154	52	2	0.29
Kim et al[21]	2006	South Korea	Asian	Gastric	PCR-RFLP	237	199	34	4	461	400	59	2	0.91
Lee et al[22]	2004	South Korea	Asian	Gastric	PCR	341	297	43	1	261	218	42	1	0.49
Lee et al[23]	2005	South Korea	Asian	Gastric	PCR-RFLP	122	112	10	0	120	103	17	0	0.40
Li et al[24]	2005	China	Asian	Gastric	PCR-RFLP	59	55	4	0	264	228	34	2	0.56
Lu et al[25]	2005	China	Asian	Gastric	PCR-DHPLC	250	214	36	0	300	274	24	2	0.08
Machado et al[26]	2003	Portugal	Caucasian	Gastric	PCR-SSCP	287	179	105	3	304	231	69	4	0.65
Melo et al[27]	2009	Brazil	Caucasian	Gastric	PCR-RFLP	30	24	5	1	100	86	13	1	0.53
Morgan et al[28]	2006	Honduras	Caucasian	Gastric	TaqMan	168	151	17	0	161	149	12	0	0.62
Perri et al[29]	2005	Italy	Caucasian	Gastric	PCR-RFLP	184	152	30	2	362	290	65	7	0.15
Rocha et al[30]	2005	Brazil	Caucasian	Gastric	PCR-RFLP	161	120	37	4	535	399	123	13	0.34
Sugimoto et al[31]	2007	Japan	Asian	Gastric	PCR-RFLP	105	101	4	0	172	169	3	0	0.91
Torres et al[32]	2004	Colombia	Caucasian	Gastric	PCR	44	41	3	0	66	56	10	0	0.51
Wu et al[33]	2002	China	Asian	Gastric	Direct sequencing	150	114	27	9	220	180	27	13	< 0.01
Wu et al[34]	2004	China	Asian	Gastric	Direct sequencing	204	163	29	12	210	171	26	13	< 0.01
Yang et al[35]	2009	South Korea	Asian	Gastric	SNaPshot	83	75	8	0	322	288	34	0	0.32
Zambon et al[36]	2005	Italy	Caucasian	Gastric	TaqMan	129	95	31	3	644	496	138	10	0.91
Garrity-Park et al[37]	2008	Ireland	Caucasian	Colorectal	PCR, sequencing	114	52	49	13	114	92	20	2	0.46
Jang et al[14]	2001	South Korea	Asian	Colorectal	PCR-RFLP	27	24	3	0	92	85	7	0	0.70
Landi et al[38]	2003	Spain	Caucasian	Colorectal	TaqMan	363	278	80	5	320	234	76	10	0.22
Li M et al[39]	2011	China	Asian	Colorectal	PCR-RFLP	180	156	15	9	180	160	19	1	0.60
Macarthur et al[40]	2005	Scotland	Caucasian	Colorectal	TaqMan	246	157	74	15	389	224	145	20	0.58
Park et al[41]	1998	South Korea	Asian	Colorectal	PCR-RFLP	140	115	24	1	328	252	72	4	0.65
Suchy et al[42]	2008	Poland	Caucasian	Colorectal	PCR-RFLP	350	254	87	9	350	248	95	7	0.55
Theodoropoulos et al[43]	2006	Greece	Caucasian	Colorectal	PCR-RFLP	222	152	56	14	200	146	44	10	0.01
Toth et al[44]	2007	Hungary	Caucasian	Colorectal	PCR-SSP	183	132	48	3	141	111	30	0	0.16
Tsilidis et al[45]	2009	United States	Caucasian	Colorectal	TaqMan	204	146	55	3	372	275	90	7	0.91
Akkiz et al[46]	2009	Turkey	Caucasian	Hepatocellular	PCR-RFLP	110	72	35	3	110	99	11	0	0.58
Ben-Ari et al[47]	2003	United States	Caucasian	Hepatocellular	PCR-SSP	10	9	11		48	42	61		NA
Chen et al[48]	2005	China	Asian	Hepatocellular	TaqMan	572	468	95	9	381	311	67	3	0.77
Heneghan et al[49]	2003	China	Asian	Hepatocellular	ASO-PCR	98	88	10	0	97	90	6	1	0.03
Ho et al[50]	2004	China	Asian	Hepatocellular	PCR-RFLP	74	37	34	3	289	225	62	2	0.30
Jeng et al[51]	2007	China	Asian	Hepatocellular	PCR-SSO	108	80	281		108	100	81		NA
Jeng JE et al[52]	2009	China	Asian	Hepatocellular	PCR-SSO	200	149	511		200	188	121		NA
Kummee et al[53]	2007	Thailand	Asian	Hepatocellular	PCR-RFLP	50	42	8	0	150	123	26	1	0.77
Migita et al[54]	2005	Japan	Asian	Hepatocellular	PCR-SSP	48	47	1	0	188	183	5	0	0.85
Niro et al[55]	2005	Italy	Caucasian	Hepatocellular	Direct sequencing	30	24	61		96	75	211		NA
Ognjanovic et al[56]	2009	United States	Caucasian	Hepatocellular	TaqMan	118	90	281		225	176	491		NA
Sakamoto et al[57]	2008	Japan	Asian	Hepatocellular	PCR-RFLP	209	205	4	0	275	270	5	0	0.88
Shi et al[58]	2011	China	Asian	Hepatocellular	PCR-RFLP	88	30	43	15	88	45	35	8	0.75
Wang et al[59]	2003	Japan	Asian	Hepatocellular	Direct sequencing	125	111	13	1	55	48	6	1	0.16
Wang et al[60]	2010	China	Asian	Hepatocellular	PCR-SSO	230	197	30	3	158	143	15	0	0.53
Duell et al[61]	2006	United States	Caucasian	Pancreatic	PCR-RFLP	260	192	63	5	859	639	198	22	0.16
Talor-wojnarowska et al[62]	2009	Poland	Caucasian	Pancreatic	PCR-RFLP	41	26	12	3	50	31	17	2	0.86
Wu GY et al[63]	2010	Germany	Caucasian	Pancreatic	PCR-RFLP	73	51	20	2	116	84	30	2	0.72
El-Omar et al[9]	2003	United States	Caucasian	Esophageal	TaqMan	161	122	34	5	210	152	52	6	0.55
Guo et al[13]	2005	China	Asian	Esophageal	PCR-RFLP	291	266	21	4	437	391	40	6	< 0.01

¹Numbers of GA+AA. P_HWE was calculated by goodness-of fit χ²-test, and P_HWE < 0.05 was considered statistically significant. PCR-DHPLC: Polymerase chain reaction-based denaturing high-performance liquid chromatography; HWE: Hardy-Weinberg equilibrium; NA: Not available; GG: Guanine/Guanine; GA: Guanine/Adenine; AA: Adenine/Adenine; PCR-RFLP: Polymerase chain reaction-restriction fragment length polymorphism.

Table 2 Stratified analysis of the tumor necrosis factor alpha polymorphism and digestive system cancers risk

Group	GA + AA vs GG			GA vs GG			AA vs GG			AA vs GA + GG
	n	OR (95%CI)	P1	n	OR (95%CI)	P1	n	OR (95%CI)	P1	n	OR (95%CI)	P1
Overall	58	1.23 (1.09, 1.38)2	< 0.00001	52	1.14 (1.01, 1.28)2	< 0.00001	44	1.43 (1.19, 1.73)	0.26	44	1.38 (1.15, 1.66)	0.55
Studies with HWE	46	1.18 (1.03, 1.34)2	< 0.00001	46	1.14 (1.00, 1.29)2	< 0.00001	38	1.54 (1.25, 1.90)	0.15	38	1.48 (1.20, 1.81)	0.40
Cancer type
Gastric	28	1.23 (1.12, 1.34)2	0.009	27	1.15 (1.04, 1.27)	0.07	22	1.38 (1.06, 1.80)	0.63	22	1.33 (1.03, 1.72)	0.67
Colorectal	10	1.17 (0.87, 1.57)2	< 0.0001	10	1.10 (0.83, 1.45)2	0.0004	9	1.45 (0.76, 2.75)2	0.02	9	1.40 (0.99, 2.00)	0.07
Hepatocellular	15	1.74 (1.20, 2.54)2	< 0.00001	10	1.58 (1.05, 2.39)2	0.002	8	2.55 (1.38, 4.70)	0.49	8	2.15 (1.19, 3.90)	0.66
Pancreatic	3	1.04 (0.79, 1.36)	0.94	3	1.04 (0.79, 1.38)	0.88	3	0.99 (0.46, 2.14)	0.63	3	0.99 (0.46, 2.13)	0.60
Esophageal	2	0.82 (0.58, 1.16)	0.89	2	0.80 (0.55, 1.15)	0.89	2	1.01 (0.42, 2.43)	0.95	2	1.05 (0.44, 2.51)	0.92
Ethnicity
Asian	27	1.24 (0.99, 1.56)2	< 0.00001	25	1.07 (0.94, 1.22)2	0.008	19	1.55 (1.11, 2.17)	0.43	19	1.47 (1.05, 2.06)	0.60
Caucasian	31	1.21 (1.05, 1.40)2	< 0.00001	27	1.17 (1.01, 1.35)2	< 0.0001	25	1.38 (1.10, 1.74)	0.18	25	1.34 (1.08, 1.67)	0.39

¹Test for heterogeneity;

²Random-effects model was used when the P for heterogeneity test was < 0.05. GG: Guanine/Guanine; GA: Guanine/Adenine; AA: Adenine/Adenine; HWE: Hardy-Weinberg equilibrium.