Summary of malignancy and programmed cell death protein ligand 1 (PD-L1) status
| Pleural effusion n | Pleural biopsy n | |
| Cases | 50 | 50 |
| Malignancy (+/−/○) | 36/7/7 | 40/10/0 |
| PD-L1 ≥1% of tumour cells (+/−/nd) | 19/6/25 | 21/14/15 |
| PD-L1 ≥50% of tumour cells (+/−/nd) | 13/12/25 | 8/27/15 |
+: positive; −: negative; ○: inconclusive; nd: not done.