Table 3.
Factors contributing to the variability of PD-L1 testing and interpretation across TNBC molecular subtypes.
| PD-L1 Clone | PD-L1 Scoring System | TNBC Molecular Classification System | TNBC Staging | ||
|---|---|---|---|---|---|
| Method | Molecular Subtype | ||||
| Sood et al. [41] | 22C3 | IC | IHC (AR, CK5/6, CK14, claudin 3 and 7, vimentin, e-cadherin, EGFR) | BL, MES, LAR, mixed, unclassifiable | eTNBC |
| Alves et al. [42] | SP142 | TC | IHC (AR, CK5, claudin, p-cadherin, EGFR), H&E (TILs) | Burstein’s classification | eTNBC |
| Phase III IMpassion 130 [29] | SP142 | IC | RNA sequencing | Burstein’s classification | mTNBC |
| Phase III NeoTRIPaPDL1 [32] | SP142 | IC | RNA sequencing | TNBCtypes by 101-gene algorithm | eTNBC |
| Phase II FUTURE [36] | SP142 | IC, TC | IHC (AR, CD8, FOXC1) | LAR, IM, BLIS, MES | mTNBC |
| Phase II Pembrolizumab + Enobosarm [40] | 22C3 | IC | IHC (AR) | LAR | mTNBC |
Abbreviations. AR: androgen receptor, BL: basal-like, BLIS: basal-like immune-suppressed, CK: cytokeratin, EGFR: epidermal growth factor receptor, FOXC1: forkhead Box C1, H&E: hematoxylin and eosin, IC: immune cells, IHC: immunohistochemistry, IM: immunomodulatory, LAR: luminal androgen receptor, MES: mesenchymal, TC: tumor cells, TILs: tumor infiltrating lymphocytes, eTNBC: early triple negative breast cancer, mTNBC: metastatic triple negative breast cancer.