Table 1.
Ligand 1 of programmed cell death protein 1 (PD-L1) quantification by immunohistochemistry in triple-negative breast carcinomas (TNBCs): summary of different scoring methods applied in different clinical studies
| Combined positive score (CPS) | Immune cell (IC) algorithm | Immune cell (IC) algorithm | |
|---|---|---|---|
| Antibody clone | 22C3 (Dako Agilent) | SP142, SP263 (Roche-Ventana) | SP263 (Roche-Ventana) |
| Target cells | Tumor cells and immune cells | Immune cells only | Immune cells only |
| Formula | (Number of PD-L1 staining cells (tumor cells, lymphocytes, macrophages)/the total viable tumor cells) ×100 | Any staining in immune cell/tumor area (tumor area = area occupied by tumor cells, associated intratumoral and continuous peritumoral stroma) | Any staining in immune cell/tumor area (tumor area = area occupied by tumor cells, associated intratumoral and continuous peritumoral stroma) |
| Cut-off | >1% | >1% | >1% |
| Minimal requirement for testing | At least 100 viable tumor cells | At least 50 tumor cells with viable stroma | At least 50 tumor cells with viable stroma |
| Clinical study in which it was originally applied (immunotherapy combination used in the experimental arm) | KEYNOTE-522 (pembrolizumab plus a sequence of carboplatin + paclitaxel followed by doxo/epirubicin + cyclophosphamide) | IMpassion130 (atezolizumab + nab-paclitaxel) | |
| Prevalence of PD-L1 positivity in the IMpassion130 | 81% | 46% | 75% |
| Analysis of specimens from other studies | Yes, post-hoc analysis of IMpassion130 samples | No | Yes, post-hoc analysis of IMpassion130 samples |