Table 2. Characteristics of eligible studies.
| First author (Year) | Country | Ethnicity | Sample size (case/control) | Genotyping methods | Matching criteria | Source of control | HCC confirmation | QC when Genotyping | SNPs | HWE(P value) | Quality scores | |
| SNP309 | Arg72Pro | |||||||||||
| Akkiz 2004 | Turkey | Caucasian | 110/110 | PCR-RFLP | Age, gender, smoking, drinking | PB | HC | Yes | MDM2 SNP309 | 0.239 | – | 9 |
| Leu 2009 | China | Asian | 58/138 | PCR-RFLP | Ethnicity | HB | NA | Yes | MDM2 SNP309 | 0.048 | – | 5 |
| Dharel 2006 | Japan | Asian | 187/296 | TaqMan assay | Drinking | HB | HC | Yes | MDM2 SNP309 | 0.724 | – | 7 |
| Ezzikouri 2011 | Morocco | African | 96/222 | PCR-RFLP | Age, gender | HB | NA | Yes | MDM2 SNP309, p53 Arg72Pro | 0.508 | 0.685 | 4 |
| Tomoda 2012 | Japan | Asian | 258/199 | MALDI-TOF | Age, gender, drinking | HB | HC | No | MDM2 SNP309 | 0.640 | – | 8 |
| Vuolo 2011 | Italy | Caucasian | 61/122 | PCR-RFLP | Age, gender | PB | PC | No | MDM2 SNP309, p53 Arg72Pro | 0.127 | 0.428 | 7 |
| Wang 2012 | China | Asian | 310/794 | PCR-RFLP | Age, gender | HB | HC | Yes | MDM2 SNP309 | 0.111 | – | 7 |
| Yoon 2008 | Korea | Asian | 287/296 | PCR-RFLP | Gender | HB | HC | No | MDM2 SNP309, p53 Arg72Pro | 0.063 | 0.978 | 8 |
| Yang 2013 | China | Asian | 350/326 | TaqMan assay | Age | HB | PC | Yes | MDM2 SNP309, p53 Arg72Pro | 0.738 | 0.636 | 8 |
| Jiang 2008 | China | Asian | 1375/2352 | PCR-RFLP | Age, gender | HB | PC | Yes | MDM2 SNP309, p53 Arg72Pro | 0.134 | 0.145 | 8 |
| Sumbul 2012 | Turkey | Caucasian | 119/119 | PCR-RFLP | Age, gender, smoking, drinking | HB | HC | Yes | p53 Arg72Pro | – | 0.022 | 9 |
| Leveri 2004 | Italy | Caucasian | 86/254 | PCR-RFLP | NA | HB | HC | No | p53 Arg72Pro | – | 0.301 | 6 |
| Yu 1999 | China | Asian | 80/328 | PCR-RFLP | Smoking, drinking | HB | PC | Yes | p53 Arg72Pro | – | 0.019 | 6 |
| Anzola 2003 | Spain | Caucasian | 97/111 | PCR-SSCP | Region | HB | NA | No | p53 Arg72Pro | – | 0.375 | 5 |
| Zhang 2012 | China | Asian | 985/992 | TaqMan assay | Age, gender | HB | PC | Yes | p53 Arg72Pro | – | 0.898 | 8 |
| Peng 2004 | China | Asian | 192/192 | PCR-RFLP | Age, gender, ethnicity | HB | PC | Yes | p53 Arg72Pro | – | 0.481 | 7 |
| Son 2013 | Korea | Asian | 157/201 | PCR-RFLP | Age, gender, drinking | HB | NA | Yes | p53 Arg72Pro | – | 0.086 | 7 |
| Xu 2011 | China | Asian | 501/548 | PCR-RFLP | Age, gender, region | PB | PC | Yes | p53 Arg72Pro | – | 0.359 | 11 |
| Zhu 2005 | China | Asian | 469/567 | PCR-RFLP | Smoking, drinking | HB | HC | Yes | p53 Arg72Pro | – | 0.321 | 8.25 |
SNP, Single nucleotide polymorphism; HC, Histologically confirmed; PC, Pathologically confirmed; NA, Not available; QC, Quality control; PB, Population–based; HB, Hospital–based; HWE, Hardy–Weinberg equilibrium in control population; PCR–RFLP, Polymerase chain reaction-restriction fragment length polymorphism; MALDI-TOF, Matrix-assisted laser desorption/ionization-time of flight mass spectrometry; PCR-SSCP, Polymerase chain reaction-single strand conformation polymorphism.