Table 1.
PD-L1 positivity in HNSCC of previous studies.
| Study | Sample size | Cut-off of PD-L1 positivity | % Positive | % Positive in HPV+ vs. HPV− | Tumor types |
|---|---|---|---|---|---|
| Lyford-Pike et al. (44) | 27 | 5% of tumor cells | 59% | 70 vs. 29% | Oropharyngeal SCC |
| Kim et al. (46) | 133 | 20% membrane staining of tumor cells | 68% | 61 vs. 71% (p = 0.274) | Oropharyngeal SCC |
| Hong et al. (49) | 99 | Any unequivocal membrane staining of tumor cells | 69.7% | 83.3 vs. 56.9% | Tonsillar cancer |
| Mattox et al. (43) | 53 | 1% membrane staining of tumor and/or immune cells | 79% | Not reported | Tougue SCC |
| Balermpas et al. (48) | 161 | 5% of tumor and/or stromal cells | 39.1% | 53 vs. 31% | HNSCC (including oral cavity, oropharynx, and hypopharynx) |
| Ou et al. (47) | 38 | 1% on both tumor and immune cells 5% on both tumor and immune cells | 71.1% 50% | No significant relationship | HNSCC (multiple sites) |