Table 1.
Characteristics of the included studies
| Study (first author) | Year | Country | Cancer type | No. of cases | Gender (M/F) | Follow-up (months) | Detection method | Outcome measurements | HR (95% CI) | NOS |
|---|---|---|---|---|---|---|---|---|---|---|
| Zeng et al17 | 2015 | PR China | PCa | 180 | NR/NR | 140 | qRT-PCR | OS | 1.76 (0.85–3.64) | 7 |
| Fu et al18 | 2017 | PR China | HCC | 310 | 252/59 | 40 | IHC | OS | 1.44 (0.96–2.17) | 8 |
| Ning et al19 | 2014 | PR China | PDA | 136 | 72/64 | 100 | qRT-PCR | OS | 0.84 (0.56–1.38) | 8 |
| Li et al20 | 2017 | PR China | HCC | 63 | 52/11 | 116 | qRT-PCR | OS | 1.15 (0.39–3.35) | 8 |
| Liu et al21 | 2017 | PR China | MG | 105 | 47/52 | 200 | IHC | OS | 4.177 (1.97–8.82) | 9 |
| Zhong et al22 | 2014 | PR China | NSCLC | 270 | 192/78 | 60 | IHC | OS | 3.810 (2.06–7.036) | 8 |
| Takahashi et al23 | 2014 | Japan | CRC | 180 | 104/76 | 180 | qRT-PCR | OS | 1.76 (0.87–3.59) | 7 |
| Zhong et al24 | 2014 | PR China | NSCLC | 270 | 192/78 | 10 | IHC | OS | 1.85 (1.20–2.83) | 8 |
| Lu et al25 | 2015 | PR China | CC | 60 | 32/28 | 100 | IHC | OS | 3.04 (1.12–8.29) | 7 |
| Wubetu et al26 | 2016 | Japan | HCC | 50 | 16/34 | 180 | qRT-PCR | OS | 2.76 (1.12–8.29) | 8 |
| Shi et al27 | 2017 | PR China | LC | 349 | 159/190 | 240 | qRT-PCR | OS/DFS | 1.749 (1.140–2.681)/1.738 (1.161–2.601) | 9 |
| Zhang et al28 | 2018 | PR China | HCC | 259 | 230/29 | 100 | qRT-PCR | OS | 1.72 (1.18–2.53) | 8 |
| Neal et al29 | 2014 | UK | CC | 103 | 57/46 | NR | IHC | OS/DFS | 1.654 (0.926–2.956)/2.393 (1.096–5.227) | 8 |
| Gu et al30 | 2017 | USA | MM | 351 | NR/NR | 80 | qRT-PCR | OS | 1.80 (0.95–3.42) | 6 |
| Marina and Saavedra31 | 2014 | USA | BC | 594 | NR/NR | 133 | qRT-PCR | DFS | 0.6 (0.5–0.9) | 6 |
Abbreviations: BC, breast cancer; CC, colon cancer; CRC, colorectal cancer; DFS, disease-free survival; F, female; HCC, hepatocellular carcinoma; IHC, immunohistochemistry; LC, lung cancer; M, male; MG, malignant glioma; MM, multiple myeloma; NOS, Newcastle-Ottawa Scale; NR, not reported; NSCLC, non-small cell lung cancer; OS, overall survival; PDA, pancreatic ductal adenocarcinoma; PCa, prostate cancer.