TABLE 1.
General characteristics of the included studies
| Author | Time | Sample size | Cancer | Control | TNM | Tissue | Country | Methods |
|---|---|---|---|---|---|---|---|---|
| (M+/M−) | (M+/M−) | |||||||
| Schmidt 12 | 2010 | 523 | 190/91 | 12/230 | I–IV | BALF | German | MSP |
| Christoph 13 | 2011 | 343 | 112/76 | 16/139 | I–IV | Plasma | German | MSP |
| Konecny 14 | 2016 | 63 | 31/6 | 4/22 | NA | BALF | German | MSP |
| Konecny 14 | 2016 | 59 | 20/11 | 6/22 | NA | Plasma | German | MSP |
| Peter 15 | 2014 | 118 | 48/27 | 1/42 | NA | BALF | German | MSP |
| Dietrich 16 | 2012 | 204 | 78/22 | 4/100 | I–IV | BALF | German | MSP |
| DietrichV 16 | 2012 | 114 | 7/51 | 0/56 | NA | Pleural effusion | German | MSP |
| Peter 17 | 2013 | 719 | 138/138 | 70/373 | NA | Pleural effusion | German | MSP |
| Li 18 | 2014 | 47 | 10/18 | 0/9 | NA | Pleural effusion | China | MSP |
| Zhang 19 | 2016 | 277 | 98/32 | 34/113 | NA | BALF | China | MSP |
| Wang 20 | 2016 | 243 | 79/44 | 8/112 | NA | BALF | China | MSP |
| Ren 21 | 2017 | 253 | 79/44 | 10/120 | I–IV | BALF | China | MSP |
| Rong 22 | 2018 | 48 | 18/20 | 2/8 | III/IV | Plasma | China | MSP |
| Wang 23 | 2018 | 120 | 57/23 | 1/39 | I–IV | Plasma | China | MSP |
| Peng 24 | 2018 | 48 | 18/20 | 2/8 | NA | Plasma | China | MSP‐DHPL |
| Lin 25 | 2019 | 202 | 29/4 | 18/151 | I–IV | BALF | China | MSP |
| Chen 26 | 2019 | 276 | 101/30 | 22/123 | I–IV | BALF | China | MSP |
| Sun 27 | 2020 | 180 | 53/67 | 3/57 | I–IV | Plasma | China | MSP |
| Sun 27 | 2020 | 180 | 74/67 | 4/56 | I–IV | BALF | China | MSP |
| Tian 28 | 2020 | 134 | 54/13 | 12/55 | Early stage | BALF | China | MSP |
| Yang 29 | 2021 | 104 | 32/16 | 14/42 | NA | Plasma | China | MSP |
Abbreviations: BALF, bronchoalveolar lavage fluid; MSP, methylation specific PCR; M+, methylation positive; M−, methylation negative; NA, not available.