Table 1.
Main characteristics of the included studies on circPRKCI as a potential biomarker candidate in human cancers.
| Author | Year | Country | Cancer type | Clinical stage | Sample size | Cut-off value | Follow-up interval (months) | Detection method | Adjuvant therapy | Survival analysis | Outcome measure | Source of HR/CI | NOS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chu et al[21] | 2020 | China | LSCC | – | 40 | Median | 80 | qRT–PCR | None | Univariate | OS and CP | KM curve | 8 |
| Hu et al[24] | 2019 | China | CC | I–II | 61 | Median | 60 | qRT–PCR | None | Univariate | OS | KM curve | 7 |
| Liu et al[25] | 2020 | China | BC | – | 54 | Median | 56 | qRT–PCR | None | Univariate | OS, DFS, and CP | KM curve | 6 |
| Liu et al[20] | 2021 | China | PTC | I–III | 48 | Median | – | qRT–PCR | None | Univariate | CP | – | 6 |
| Meng et al[19] | 2020 | China | LC | – | 60 | N/A | 60 | qRT–PCR | None | Univariate | OS | KM curve | 8 |
| Qiu et al[17] | 2018 | China | LUAC | I–III | 89 | N/A | 84 | qRT–PCR | N/A | Multivariate | OS and CP | KM curve | 9 |
| Sui et al[26] | 2021 | China | LUAC | I–IV | 50 | N/A | 60 | qRT–PCR | None | Univariate | OS | KM curve | 8 |
| Wang et al[27] | 2019 | China | TC | I–IV | 57 | Median | 72 | qRT–PCR | N/A | Univariate | OS and CP | Raw data | 8 |
| Wang et al[28] | 2018 | China | NSCLC | I–IV | 159 | Median | 60 | qRT–PCR | None | Multivariate | OS and CP | Raw data | 9 |
| Wu et al[29] | 2019 | China | GC | I–IV | 50 | N/A | 60 | qRT–PCR | N/A | Univariate | OS | KM curve | 8 |
| Xin et al[30] | 2019 | China | GBM | – | 157 | N/A | 60 | qRT–PCR | None | Univariate | OS and DFS | KM curve | 8 |
| Zhang et al[31] | 2019 | China | TC | I–IV | 50 | Median | 60 | qRT–PCR | None | Univariate | OS | KM curve | 8 |
| Zhou et al[18] | 2020 | China | HCC | I–IV | 106 | N/A | 60 | qRT–PCR | None | Univariate | OS and CP | KM curve | 8 |
| Zhu et al[32] | 2018 | China | HCC | I–III | 49 | N/A | 60 | qRT–PCR | None | Univariate | OS | KM curve | 8 |
| Zou et al[33] | 2018 | China | NSCLC | I–IV | 79 | Median | 80 | qRT–PCR | None | Multivariate | OS and CP | Raw data | 9 |
BC: Bladder cancer; CC: Cervical cancer; CP: Clinical parameters; DFS: Disease-free survival; GBM: Glioblastoma; GC: Gastric cancer; HCC: Hepatocellular carcinoma; HR/CI: Hazard ratios with corresponding 95% confidence interval; KM curve: Kaplan–Meier curve; LC: Lung cancer; LSCC: Laryngeal squamous cell cancer; LUAC: Lung adenocarcinoma; N/A: Not available; NOS: Newcastle–Ottawa Scale; NSCLC: Non-small cell lung cancer; OS: Overall survival; PTC: Papillary thyroid cancer; qRT-PCR: Quantitative real-time polymerase chain reaction; TC: Thyroid cancer; –: Not available.