Table 1 Characteristics of the patients included in the meta-analysis
From: The prognostic value of IDO expression in solid tumors: a systematic review and meta-analysis
Study | Year | Country | Cancer type | Case (n) | Age (Median/Mean, years) | Tumor stage (I/II/III/IV) | Follow-up (Median/Mean, months) | Study type | Method | Cut off value | Endpoints | NOS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Gerald. et al | 2006 | Austria | Colorectal cancer | 143 | NA | 29/24/78/12 | 51.8a | Retrospective | IHC | High expression: score (5–12) Low expression: score (0–4) | OS | 8 |
K. et al | 2006 | Japan | Endometrial cancer | 80 | 57.2a | 54/10/10/6 | 71.6b | Retrospective | IHC | High expression: score (4–6) Low expression: score (0–3) | OS, PFS | 8 |
Rainer. et al | 2007 | Japan | Renal cell carcinoma | 55 | NA | 22/33 | NA | Retrospective | qPCR | High expression: Above the 80th percentile | OS | 6 |
Ke. et al | 2008 | China | Hepatocellular carcinoma | 138 | NA | NA | NA | Retrospective | IHC | High expression: score (5–9) Low expression: score (0–4) | OS | 8 |
Kazuhiko. et al | 2008 | Japan | Endometrial Cancer | 65 | 57.7a | 44/6/9/6 | 72b | Retrospective | IHC | High expression: score (4–5) Low expression: score (0–3) | OS, PFS | 8 |
Hiroshi. et al | 2009 | Japan | Osteosarcoma | 47 | 15b | 0/47/0/0 | 67.4b | Retrospective | IHC | High expression: score (4) Low expression: score (0–3) | OS | 7 |
Tomoko. et al | 2010 | Japan | Cervical cancer | 112 | NA | 67/45/0/0 | NA | Retrospective | IHC | High expression: > 50% of tumor cells were stained | OS, PFS | 7 |
Jacek. et al | 2011 | Poland | Vulvar squamous cell carcinoma | 76 | 69.5b | NA | 51.23b | Retrospective | IHC | > 50% of tumor cells were stained with clusters of higher intensity of expression | OS | 8 |
Reinhart. et al | 2011 | Belgium | Melanoma | 116 | 52b | NA | 71b | Prospective | IHC | Almost none/weak versus strong IDO expression | OS, PFS | 9 |
Renske. et al | 2012 | Netherland | Endometrial carcinoma | 355 | 64b | 196/58/77/44 | 63.6b | Prospective | IHC | High expression: score (4–6) Low expression: score (0–3) | DFS | 8 |
Jin. et al | 2013 | China | Laryngeal squamous cell carcinoma | 187 | 52.4b | 20/58/88/21 | 48.56a | Retrospective | IHC | High expression: score (3–4) Low expression: score (0–2) | OS, DFS | 9 |
Yunlong. et al | 2015 | China | Esophageal squamous cell cancer | 196 | 54b | 113(I–II)/83(III–IV) | NA | Prospective | IHC | High expression: score (5–12) Low expression: score (0–4) | OS | 8 |
Maciej. et al | 2015 | Poland | Melanoma | 48 | 56.9b | NA | 30.3b | Retrospective | IHC | High expression: score > 47.39 Low expression: score ≤ 47.39 | OS | 6 |
Ahlem. et al | 2016 | Tunisia | Nasopharyngeal carcinoma | 71 | NA | 10(I–II)/53(III–IV) | 30b | Prospective | IHC | High expression: score (4–5) Low expression: score (0–3) | OS, PFS | 7 |
Hao. et al | 2016 | China | Gastric adenocarcinoma | 357 | 60.3a | 80/79/198/0 | 41b | Retrospective | IHC | With the X-tile software, the cut-off point was 282, 51% patients were separated into the IDO high expression subgroup | OS | 7 |
Tao. et al | 2017 | China | Pancreatic cancer | 80 | NA | 10(I–II)/53(III–IV) | 40b | Prospective | IHC | High expression: score (> 4) Low expression: score (≤4) | OS | 8 |
Tvrtko. et al | 2017 | Croatia | Bladder carcinomas | 74 | 65.3a | NA | NA | Prospective | qPCR | IDO-positive group, in which expression of IDO gene was detected, regardless of the level of expression. | OS | 7 |
Daniel. et al | 2017 | USA | Breast cancer | 362 | NA | 278(I–II)/63(III–IV) | NA | Retrospective | IHC | Median cut-point was used to stratify IDO1 scores in low and high statuses. | OS | 8 |
Lijie. et al | 2017 | USA | Glioblastoma | 148 | NA | NA | NA | Prospective | qPCR | IDO1 mRNA levels were stratified into IDO1- low and -high expressing groups based on the determined cutoff values. | OS | 8 |
Wenjuan. et al | 2018 | China | Colorectal cancer | 95 | NA | NA | NA | Retrospective | IHC | High expression: score (2–3) Low expression: score (0–1) | OS | 7 |
Yufeng. et al | 2018 | Taiwan (China) | Thymic carcinoma | 69 | 54a | 1/3/45/20 | 46b | Retrospective | IHC | High expression: score (2–3) Low expression: score (0–1) | OS, PFS | 8 |
Hiroto. et al | 2018 | Japan | Esophageal cancer | 182 | 66.5a | 69/63/41/9 | NA | Retrospective | IHC | High expression: score (2–3) Low expression: score (0–1) | RFS | 7 |
Yuki. et al | 2018 | Japan | Esophageal Cancer | 305 | 66a | 123/80/102/0 | 44.4b | Prospective | IHC | (0; no expression, 1; weak expression, 2; moderate expression or 3; strong expression) | OS | 9 |
Masaaki. et al | 2018 | Japan | Gastric Cancer | 60 | 67.8a | 0/0/60/0 | 41a | Retrospective | IHC | A total score of greater than 4+ was defined as IDO positive expression | OS, DFS | 8 |
Tamkin. et al | 2019 | Australia | Malignant pleural mesothelioma | 67 | 65b | NA | NA | Retrospective | IHC | Negative Positive (>  0%) | OS | 7 |
Wenjuan. et al | 2019 | China | Adenosquamous Lung Carcinoma | 183 | 58b | 52/41/71/19 | NA | Retrospective | IHC | High- and low-expression based on the determined cutoff values. | OS | 8 |
Devarati. et al | 2019 | USA | Anal cancer | 63 | 61b | 7/24/9/21 (2 unknown) | 35b | Retrospective | IHC | Positive (> 50% IDO1 expression) | OS | 8 |
Julia. et al | 2019 | Germany | Rectal cancer | 91 | 64b | NA | NA | Retrospective | IHC | High expression: score (3–6) Low expression: score (0–2) | OS, DFS | 8 |
Nadia. et al | 2019 | Tunisia | Vulvar squamous cell carcinoma | 61 | 65.61a | 29/4/26/2 | NA | Retrospective | IHC | High expression: score (3) Low expression: score (0–2) | OS, DFS | 7 |
Sha. et al | 2019 | China | Esophageal squamous cell carcinoma | 158 | 56b | 0/34/124/0 | 40.2b | Retrospective | IHC | Positive (> 50% IDO1 expression) | RFS | 8 |
Yuhshyan. et al | 2019 | Taiwan (China) | Bladder cancer | 108 | 68a | 45/43/19/1 | 45b | Retrospective | IHC | Strongly Positive (> 25% IDO1 expression) | OS, PFS | 8 |