Table 1. Demographic baseline and PD-L1 expression assessment of the studies.
| First author and year of publication | Classification of lung cancer | Ethnicity | Assessment of IHC staining | Cut off for PD-L1 positive | Reference |
|---|---|---|---|---|---|
| Kim 2015 | SQCC | Asia | Percentage | 10% | (15) |
| D’Incecco 2015 | NSCLC | Non-Asia | H-score | 10 | (14) |
| Cooper 2015 | NSCLC | Non-Asia | Percentage | 50% | (16) |
| Chang 2015 | LLC | Asia | Percentage | 5% | (17) |
| Yang 2014 | AD | Asia | Percentage | 5% | (18) |
| Yang 2016 | SQCC | Asia | Percentage | 5% | (19) |
| Zhang 2014 | AD | Asia | Quickscore | 8 | (20) |
| Tang 2015 | NSCLC | Asia | H-score | 5 | (13) |
| Rizvi 2015 | NSCLC | Non-Asia | Percentage | 1% | (10) |
| Ji 2016 | AD | Asia | H-score | 10 | (21) |
| Scheel 2016 | NSCLC | Asia | Percentage | 1% | (22) |
| Chang 2016 | pleomorphic carcinoma | Asia | Percentage | 5% | (23) |
| Fang 2015 | LLC | Asia | Percentage | 5% | (24) |
| Inoue 2016 | NSCLC | Asia | H-score | 5 | (25) |
| Koh 2015 | AD | Asia | Percentage | 5% | (26) |
| Tao 2016 | SCLC | Asia | Percentage | 5% | (27) |
| Ameratunga 2016 | NSCLC | Non-Asia | H-score | 100 | (28) |
| Velcheti 2014 | NSCLC | Non-Asia | NA | NA | (29) |
| Mu 2011 | NSCLC | Asia | H-score | Median value | (30) |
| Chen 2013 | NSCLC | Asia | H-score | 9 | (31) |
| Chen 2012 | NSCLC | Asia | H-score | 3 | (32) |
| Takada 2016 | AD | Asia | Percentage | 1% | (33) |
| Song 2016 | AD | Asia | Percentage | 5% | (34) |
| Song 2016 | SQCC | Asia | H-score | 5 | (35) |
| Calles 2015 | NSCLC | Non-Asia | Percentage | 5% | (36) |
| Shimoji 2016 | NSCLC | Asia | NA | NA | (37) |
| Schmidt 2015 | NSCLC | Non-Asia | Percentage | 5% | (38) |
| Sorensen 2016 | NSCLC | Non-Asia | Percentage | 1% | (39) |
| Chen 2016 | NSCLC | Asia | Allred score | 1 | (40) |
| Jiang 2015 | LLC | Asia | Percentage | 5% | (41) |
| Sun 2016 | NSCLC | Asia | Percentage | 1% | (42) |
| Lin 2015 | AD | Asia | H score | Mean H-score | (43) |
| Jia 2016 | NSCLC | Asia | Percentage | 10% | (44) |
| Huynh 2016 | AD | Non-Asia | Percentage | 5% | (45) |
Quickscore = SI (staining intensity) × PPC (percentage of positive cells score). SI was determined as: 0, negative; 1, weak; 2, moderate; and 3, strong. PPC was defined as: 1, 0–4%; 2, 5–19%; 3, 20–39%; 4, 40–59%; 5, 60–79%; 6, 80–100%. H-score = summation (1+i)pi. PD-L1, programmed death-ligand 1; AD, adenocarcinoma; LLC, lymphoepithelioma-like carcinoma; NSCLC, non-small cell lung cancer; SQCC, squamous cell lung carcinoma.