Table 1. Characteristics of studies included in the meta-analysis.
| First author | Year | Country | HIF isoforms | Number of total patient(positive) | Expression location | Method | Antibody source | Antibody dilution | Definition of HIF positive | HR estimation | Quality score |
| Xie | 2012 | China | HIF-1α | 93(46) | C and N | IHC | Santa Cruz | 1∶100 | Multiplying the intensitys core by expressions core≥median value | NA | 8 |
| Korkeila | 2011 | Finland | HIF-1α | 168(68) | N | IHC | BD | 1∶100 | Weak,moderate or strong staining | HR for DFS | 7 |
| Shioya | 2011 | Japan | HIF-1α | 50(21) | N | IHC | Neomarkers | 1∶20000 | 40% | HR for OS and survival curves for DFS | 8 |
| Havelund | 2011 | Denmark | HIF-1α | 86(39) | N | IHC | BD | 1∶75 | Summing the intensitys core and expressions core≥3 | Survival curves for OS | 7 |
| Saigusa | 2011 | Japan | HIF-1α | 52(NA) | NA | RT-PCR | NA | NA | 0.0212 for PFS and 0.1274 for OS | HR for OS and DFS | 7 |
| Mohammed | 2011 | Spain | HIF-2α | 154(NA) | NA | RT-PCR | NA | NA | NA | NA | 6 |
| Kwon | 2010 | Korea | HIF-1α | 311(196) | N | IHC | Novus | 1∶50 | 10% | HR for OS and DFS | 7 |
| Wu | 2010 | China | HIF-1α | 68(30) | C and N | IHC | Abcam | 1∶200 | Multiplying the intensitys core by expressions core≥5 | NA | 6 |
| Zheng | 2010 | China | HIF-1α | 62(39) | C and N | IHC | Boster | 1∶400 | Summing the intensitys core and expressions core≥5 | NA | 5 |
| Baba | 2010 | United States | HIF-1α | 731(142) | C | IHC | Santa Cruz | 1∶500 | Moderate staining>50% or Any strong staining | HR for OS | 7 |
| HIF-2α | 695(322) | C | IHC | Santa Cruz | 1∶250 | Weak to strong expression. | HR for OS | ||||
| Toiyama | 2010 | England | HIF-1α | 40(NA) | NA | RT-PCR | NA | NA | 0.3649 | HR for DFS | 5 |
| Gao | 2009 | China | HIF-1α | 71(39) | C and N | IHC | Zymed | 1∶50 | Any staining | HR for OS | 8 |
| Jubb | 2009 | Austrialia | HIF-2α | 155(60) | N | IHC | BD | NA | Any staining | HR for OS | 6 |
| Rajaganeshan | 2009 | England | HIF-1α | 55(25) | C or N | IHC | Abcam | 1∶100 | >10% in nuclear or distinct, Strong staining in cytoplasm | HR for DFS | 4 |
| Schmitz | 2009 | Germany | HIF-1α | 129(34) | N | IHC | Transduction Laboratories | 1∶10 | Any staining | NA | 8 |
| Rasheed | 2009 | England | HIF-1α | 90(48) | C and N | IHC | Novus | 1∶500 | NA | HR for DFS | 7 |
| HIF-2α | 90(58) | C and N | IHC | Novus | 1∶100 | NA | NA | ||||
| Cleven | 2007 | Holand | HIF-2α | 133(110) | N | IHC | BD | 1∶120 | 5% | HR for OS | 4 |
| Lu | 2006 | China | HIF-1α | 30(19) | N | IHC | NA | 1∶200 | 10% | Survival curves for OS | 7 |
| Theodoropoulos | 2006 | Greece | HIF-1α | 92(44) | N | IHC | Stress Gene | 1∶1200 | Moderate or strong staining | HR for OS and DFS | 7 |
| Yoshimura | 2004 | Japan | HIF-1α | 87(39) | N | IHC | Novus | 1∶1000 | 5% | Survival curves for OS | 6 |
| HIF-2α | 87(26) | N | IHC | Novus | 1∶1000 | 5% | Survival curves for OS | ||||
| Kuwai | 2003 | Japan | HIF-1α | 139(81) | C and N | IHC | Dako | 1∶1000 | 9.60% | NA | 6 |
| Shimomura | 2013 | Japan | HIF-1α | 64(20) | C | IHC | Novus | 1∶50 | Sum the intensity and percentage scores≥6 | Survival curves for OS | 7 |
| Yu | 2012 | China | HIF-1α | 124(67) | C | IHC | Abcam | 1∶100 | 10% | Survival curves for OS | 6 |
NA, not available; HR, hazard ratio; OS, overall survival; DFS, disease free survival; IHC, immunohistochemistry; C, cytoplasm; N, nucleus.