Table 1. Characteristics of studies included in the meta-analysis.
| Study | Year | Country | Ethnicity | Cancer type | Source of controls | Genotype methods | Genotype (case/control) | HWE (P value) | |||
| Total | CC | CT | TT | ||||||||
| -260C/T | |||||||||||
| Andrie [9] | 2009 | USA | Caucasian | Childhood lymphomas | HB | PCR | 83/83 | 31/18 | 39/42 | 13/23 | 0.886 |
| Castano-Rodriguez [10] | 2013 | Malaysia, Singapore | Asian | Gastric | HB | Real time-PCR | 70/214 | 18/34 | 38/108 | 14/72 | 0.537 |
| Companioni [11] | 2013 | Mixed | Caucasian | Gastric | PB | Illumina Beadstation | 1192/352 | 307/103 | 621/173 | 264/76 | 0.833 |
| Guo [12] | 2006 | China | Asian | Colorectal | PB | PCR-RFLP | 110/160 | 35/25 | 34/77 | 41/58 | 0.947 |
| Hao [13] | 2010 | China | Asian | Gastric | HB | PCR-RFLP | 90/100 | 7/18 | 45/52 | 38/30 | 0.581 |
| Hold [14] | 2009a | Polish | Caucasian | Gastric | PB | TaqMan | 327/389 | 110/131 | 134/176 | 83/82 | 0.112 |
| Hold [14] | 2009b | USA | Caucasian | Gastric | PB | TaqMan | 306/211 | 91/52 | 147/108 | 68/51 | 0.730 |
| Hold [14] | 2009c | USA | Caucasian | Esophageal | PB | TaqMan | 158/211 | 50/52 | 74/108 | 34/51 | 0.730 |
| Landi [15] | 2006 | Spain | Caucasian | Colorectal | HB | TaqMan | 281/265 | 62/65 | 151/137 | 68/63 | 0.580 |
| Miedema [16] | 2012 | Nertherland | Caucasian | Childhood ALL | PB | PCR | 186/182 | 46/28 | 81/101 | 59/53 | 0.077 |
| Min [17] | 2012 | China | Asian | Prostate | HB | PCR-LDR | 168/208 | 73/102 | 71/80 | 24/26 | 0.105 |
| Tahara [18] | 2007 | Japan | Asian | Gastric | HB | PCR-RFLP | 149/94 | 37/14 | 80/53 | 32/27 | 0.147 |
| Wu [19] | 2006a | China | Asian | Gastric | HB | PCR | 204/210 | 52/54 | 102/102 | 50/54 | 0.679 |
| Wu [19] | 2006b | China | Asian | MALT lymphomas | HB | PCR | 70/210 | 17/54 | 29/102 | 24/54 | 0.679 |
| Yu [20] | 2011 | China | Asian | ALL | PB | PCR-RFLP | 174/539 | 29/80 | 55/259 | 90/200 | 0.796 |
| Zhang [21] | 2011 | China | Asian | Gastric | HB | PCR-RFLP | 160/296 | 85/141 | 61/135 | 14/20 | 0.102 |
| Zhao [22] | 2007 | China | Asian | Gastric | PB | PCR-RFLP | 470/470 | 33/56 | 225/227 | 212/187 | 0.305 |
| -651C/T | |||||||||||
| Miedema [16] | 2012 | Nertherland | Caucasian | ALL | PB | PCR | 188/181 | 108/96 | 66/77 | 14/8 | 0.124 |
| Yu [19] | 2011 | China | Asian | ALL | PB | PCR-RFLP | 174/539 | 99/287 | 60/213 | 15/39 | 0.952 |
| Zhao [22] | 2007 | China | Asian | Gastric | PB | PCR-RFLP | 470/470 | 257/257 | 191/183 | 22/30 | 0.735 |
HWE: Hardy-Weinberg equilibrium; PB: population-based; HB: hospital-based; PCR-RFLP: polymerase chain reaction-restriction fragment length polymorphism; PCR-LDR: polymerase chain reaction-ligase detection reaction;
ALL: acute lymphoblastic leukemia; MALT lymphomas: gastric mucosa-associated lymphoid tissue lymphoma.