HIF-1α -1790G>A polymorphism significantly increases the risk of digestive tract cancer: A meta-analysis

Table 1 Baseline characteristics of eligible studies

Ref.	Year	Country	Ethnicity	Control	Cancer type	SNP	Cases	Controls
Alves et al[21]	2012	Brazil	Latin America	HB	Oral cancer	C1722T, G1790A	40	88
Ruiz-Tovar et al[22]	2012	Spain	Caucasian	PB	Pancreatic cancer	C1722T, G1790A	59	159
Wang et al[7]	2009	China	Asian	HB	Pancreatic cancer	C1722T, G1790A	263	271
Kang et al[15]	2011	Korea	Asian	HB	Colorectal cancer	C1722T	50	50
Shieh et al[24]	2010	China	Asian	HB	Oral cancer	C1722T, G1790A	305	96
Hsiao et al[25]	2010	China	Asian	HB	Hepatocellular carcinoma	C1722T, G1790A	102	347
Knechtel et al[17]	2010	Austria	Caucasian	HB	Colorectal cancer	C1722T, G1790A	381	1209
Chen et al[26]	2009	China	Asian	PB	Oral cancer	C1722T, G1790A	347	174
Li et al[16]	2009	China	Asian	HB	Gastric cancer	C1722T, G1790A	87	106
Muñoz-Guerra et al[27]	2009	Spain	Caucasian	PB	Oral cancer	C1722T, G1790A	155	139
Fransén et al[28]	2006	Sweden	Caucasian	HB	Colorectal cancer	C1722T, G1790A	198	258
Ling et al[29]	2005	China	Asian	PB	Esophageal cancer	C1722T	95	104
Kuwai et al[30]	2004	Japan	Asian	PB	Colorectal cancer	C1722T	100	100

HB: Hospital-based studies; PB: Population-based studies; SNP: Single nucleotide polymorphism.

Table 2 Meta-analysis results of -1772C>T polymorphism

	Dominant comparison		Allele comparison		Heterozygote comparison
	OR (95%CI)	Phet	OR (95%CI)	Phet	OR (95%CI)	Phet
Overall	1.156 (0.839-1.593)	0.007	1.325 (0.846-2.076)	< 0.001	0.853 (0.502-1.450)	< 0.001
Ethnicity
Caucasian	1.053 (0.842-1.317)	0.381	1.075 (0.795-1.454)	0.011	0.459 (0.174-1.211)	0.060
Asian	1.302 (0.748-2.266)	0.007	1.169 (0.667-2.049)	< 0.001	1.132 (0.628-2.040)	0.009
Source of control
HB	1.314 (0.884-1.954)	0.014	1.661 (0.755-3.656)	< 0.001	1.153 (0.633-2.099)	0.009
PB	0.898 (0.498-1.620)	0.086	1.163 (0.698-1.938)	0.089	0.482 (0.166-1.405)	0.004
Cancer types
OC	1.063 (0.643-1.757)	0.304	2.517 (0.705-8.980)	< 0.001	0.917 (0.444-1.895)	0.135
PC	1.388 (0.542-3.555)	0.032	1.753 (1.225-2.508)1	0.349	0.500 (0.018-14.015)	0.001
CRC	1.118 (0.573-2.182)	0.015	0.262 (0.011-6.380)	0.024	0.241 (0.011-5.509)	0.027
HWE
No	0.777 (0.466-1.296)	0.832	3.221 (0.673-15.414)	< 0.001	0.250 (0.051-1.211)	0.139
Yes	1.260 (0.873-1.818)	0.007	1.149 (0.723-1.826)	0.009	1.091 (0.660-1.803)	0.005
Sample size
Small	0.958 (0.621-1.479)	0.031	1.192 (0.680-2.089)	< 0.001	0.658 (0.362-1.197)	0.007
Large	1.569 (1.049-2.345)1	0.125	1.983 (1.325-2.969)1	0.867	1.994 (1.307-3.042)1	0.529

¹Significant association. Phet: P value of heterogeneity; HB: Hospital-based studies; PB: Population-based studies; OC: Oral cancer; PC: Pancreatic cancer; CRC: Colorectal cancer.

Table 3 Meta-analysis results of -1790G>A polymorphism

	Dominant comparison		Allele comparison		Heterozygote comparison
	OR (95%CI)	Phet	OR (95%CI)	Phet	OR (95%CI)	Phet
Overall	3.252 (1.661-6.368)1	< 0.001	4.455 (1.938-10.241)1	< 0.001	2.677 (1.677-4.273)1	< 0.001
Ethnicity
Caucasian	1.882 (0.627-5.644)	< 0.001	2.881 (0.943-8.807)	0.009	1.898 (0.411-8.761)	0.002
Asian	2.921 (1.909-4.470)1	0.163	2.793 (1.877-4.158)1	0.195	2.891 (1.890-4.422)1	0.165
Source of control
HB	3.258 (1.331-7.977)1	< 0.001	4.904 (1.375-17.489)1	< 0.001	2.521 (1.526-4.167)1	0.094
PB	3.516 (1.340-9.229)1	0.026	3.923 (1.894-8.128)1	0.084	2.729 (0.823-9.053)1	0.011
Cancer types
OC	7.919 (1.582-39.636)1	< 0.001	9.663 (1.312-71.149)1	< 0.001	3.165 (1.264-7.924)1	0.019
PC	2.499 (0.929-6.726)	0.098	3.030 (1.946-4.716)1	0.418	1.611 (0.241-10.760)	0.019
CRC	0.971 (0.571-1.650)	0.454
Sample size
Small	4.127 (1.511-11.267)1	< 0.001	4.976 (1.457-16.996)1	< 0.001	2.351 (1.180-4.682)1	0.007
Large	2.186 (0.863-5.537)	0.001	3.313 (2.214-4.959)1	0.969	3.492 (2.298-5.307)1	0.690

¹Significant association. OR: Odds ratio.