Table 3.
Summarized Key Studies Showing PD-L1 Expression in Breast Carcinoma Cells Assessed Using Immunohistochemistry Staining and Its Clinicopathologic Relevance
| First Author (Year) | No. of Cases | Antibody Clone | Cutoff for PD-L1 Positivity (Cell Compartment Evaluated) | PD-L1–Positive Rate | Clinicopathologic Variables Significantly Associated With Positive PD-L1 Expression | Survival Variables Associated With PD-L1 Positivity |
|---|---|---|---|---|---|---|
| Ghebeh (2006)27 | 44 breast cancer samples (frozen section) | MIH1 | Any positive cells (cell membrane and/or cytoplasm) | 34.0% | ER–, PR– | NA |
| Mittendorf (2014)28 | 120 TNBCs (TMA) | 5H1 | >5% (cell membrane) | 19.0% | NA | NA |
| Muenst (2014)14 | 650 breast cancer samples (TMA) | Rabbit polyclonal antibody | H-score ≥100 (cell membrane and/or cytoplasm) | 23.4% | Higher grade and Ki-67 index, larger size, positive nodal status, ER– | Shorter OS in univariate and multivariate analysis |
| Qin (2015)16 | 870 breast cancer samples (TMA) | Rabbit polyclonal antibody | >5% (cell membrane and/or cytoplasm) | 21.7% (55.9% in TNBC) | Larger size, higher grade, LVI, ER–, PR– | Shorter DFS, OS |
| Ali (2015)15 | 3,916 breast cancer samples (TMA) | Rabbit polyclonal antibody | >1% (not specified) | 1.7% | Basal-like subtype | Better DFS (P = .08) in ER– tumors |
| Guo (2016)23 | 183 TNBCs (TMA) | SP142 | Not specified (cell membrane and/or cytoplasm) | 8.7% | Higher grade | Not associated with survival |
| Cimino-Mathews (2016)21 | 45 breast cancer samples (whole sections) | 5H1 | ≥5% (cell membrane) | 21.0% | Higher grade | Less likely to have distant metastasis |
| Beckers (2016)20 | 161 TNBCs (TMA) | E1L3N | ≥1% and ≥5% (cell membrane) | 64.0% and 60.0%, respectively | Not associated with any variables | Not associated with survival |
| ≥1% and ≥5% (cell cytoplasm) | 80.0% and 77.8%, respectively | Not associated with any variables | Lower risk of cancer- specific death | |||
| Bae (2016)18 | 465 breast cancer samples (TMA) | E1L3N | H-score ≥100 (cell membrane and/or cytoplasm) | 13.5% | Higher grade and Ki-67 index, negative nodal status, ER–, PR–, HER2+ | Longer DFS and OS in univariate analysis |
| Li (2016)24 | 136 TNBCs (whole sections) | E1L3N | Any positive cells (cell membrane) | 21.0% | NA | Not associated with DFS |
| Baptista (2016)19 | 192 breast cancer samples (TMA) | Rabbit polyclonal antibody | Allred score >0 (cell membrane and/or cytoplasm) | 56.6% | Larger size, positive nodal status, ER–, distant recurrence | Better OS |
| Li (2016)25 | 501 breast cancer samples (whole sections) | ab58810 | H-score ≥100 (cell membrane and/or cytoplasm) | 46.1% | Higher grade, aggressive intrinsic subtype, ER–, PR– | Shorter OS |
| Mori (2017)43 | 248 TNBCs (whole sections) | E1L3N | ≥1% (cell membrane) | 41.5% | Higher grade, and Ki-67 index | Not associated with prognosis |
DFS, disease-free survival; ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; LVI, lymphovascular invasion; NA, not available; OS, overall survival; PD-L1, programmed death ligand 1; PR, progesterone receptor; TMA, tissue microarray; TNBC, triple-negative breast cancer.