Table 4.
Studies of PD-L1 and PD-1 in Thymoma and Thymic Carcinoma, Including Expression Patterns and Prognostic Implications
| Source | Thymoma, n | Thymic Carcinoma, n | PD-1 Antibody | PD-L1 Antibody | PD-1 Positivity Thymoma, n (%) | PD-L1 Positivity Thymoma, n (%) | PD-1 Positivity Thymic Carcinoma, n (%) | PD-L1 Positivity Thymic Carcinoma, n (%) | PD-L1 Prognostic of Survival | PD-1 Prognostic of Survival |
|---|---|---|---|---|---|---|---|---|---|---|
| Brown et al., 200350 | 26 | 8 | NA | 29E.2A3 29E.5A9 |
NA | 21 (81)a | NA | 7 (88) | NA | NA |
| Katsuya et al., 201531 | 101 | 38 | NAT105 (Abcam, rabbit monoclonal antibody) | E1L3N (Cell Signaling Technology) | NA | 22 (23) | 23 (62) | 26 (70) | No; p = 0.408 |
No; p = 0.836 |
| Yokoyama et al., 201649 | 82 | 0 | NA | EPR1161 (Abcam, rabbit monoclonal antibody) | NA | 44 (53.7) | NA | NA | No; p = 0.957 |
NA |
| Yokoyama et al., 201625 | 0 | 25 | NAT105 (Abcam, rabbit monoclonal antibody) | EPR1161 (Abcam, rabbit monoclonal antibody) | NA | NA | NA | 20 (80) | Yes; high PD-L1 associated with longer OS (p = 0.010) | Yes; PD-1 associated with worse prognosis (HR = 1.496, p = 0.037)b |
| Katsuya et al., 201645 | 12 | 18 | NAT105 (Abcam, rabbit monoclonal antibody) | E1L3N (Cell Signaling Technology) | 4 (44)c | 6 (67) | 8 (47) | 7 (41) | Nod | No |
| Padda et al., 201524 | 65 | 4 | NA | Sino Biological clone 15 (rabbit monoclonal antibody) | NA | 44 (68)e | NA | 3 (75) | Yes; high PD-L1 expression associated with worse OSf | NA |
| Marchevsky and Walts, 201746 | 38 | 8 | MRQ22; Cell Marque | Clone SP142; Spring BioScience | 24 (63) | 35 (92) | 3 (37.5) | 4 (50) | NA | NA |
| Weissferdt et al., 201748 | 74 | 26 | EPR4877 (Abcam, rabbit monoclonal antibody) | E1L3N (Cell Signaling Technology) | 46 (62) | 47 (64) | 6 (23) | 14 (54) | No; thymoma p = 0.4180 or thymic carcinoma p = 0.4628 | No; p = 0.3942 or thymic carcinoma p = 0.2137 |
| Tiseo et al., 201747 | 87 | 20 | NA | E1L3N (Cell Signaling Technology) | NA | 15 (18) | NA | 13 (65) | No; p = 0.604 | No; p = 0.206 |
| Present study | 32 | 3 | NAT105 (Abcam, rabbit monoclonal antibody) | 22C3 (Dako North America) | 26 (81) | 26 (81) | 1 (33) | 3 (100) | No; p = 0.119g | NA; p = 0.469 |
Manufacturers noted are Abcam (Cambridge, United Kingdom), Cell Marque Corporation (Rocklin, California), Cell Signaling Technology (Danvers, Massachusetts), Spring Bioscience (Pleasanton, California), and Dako North America (Carpinteria, California).
Eleven of 11 invasive (100%) thymoma samples and 10 of 15 (67.77%) noninvasive thymoma samples.
Lower PD-1 expression among tumor infiltrating lymphocytes was associated with poorer OS in patients with thymic carcinoma only.
For analysis in this study, evaluable tumor samples included 9 thymomas and 17 thymic carcinomas.
PD-L1 expression was not prognostic in either thymic carcinoma (p = 0.449) or thymoma (p = 0.624). PD-1 expression was not prognostic in either thymic carcinoma (p = 0.650) or thymoma (p = 0.689).
All thymic neoplastic and control samples stained positive for PD-L1; samples were analyzed according to PD-L1 high expression versus PD-L1 low expression.
In unadjusted analysis, no difference in OS was noted, but in age and gender adjusted analysis PD-L1high versus PD-L1 low had worse OS (p = 0.035), but included both thymoma and thymic carcinoma together. When adjusted for stage, no significant association with OS was noted (p = 0.071).
Reported for thymoma cohort, since no difference able to report since three thymic carcinoma patients had PD-L1 expression.
PD-L1, programmed death ligand 1; PD-1, programmed death 1; NA, not available; OS, overall survival; HR, hazard ratio.