Table 2.
The reported PD-L1 formats.
| Format | Location | Structure | Source | Possible functions | Treatment response | Detection* | References |
|---|---|---|---|---|---|---|---|
| mPD-L1 | Membrane | Integrity | Endogenous translation | Bind with PD-1 for immune regulation | Antibody, gene, and chemo-inhibitor | WB, IHC | (11, 12) |
| cPD-L1 | Cytoplasm | – | Endogenous translation | Transfer to membrane, shorten disease-free survival, and cell growth and migration | Gene and chemo-inhibitor | WB, IHC | (23, 28) |
| nPD-L1 | Nuclei | – | – | Enhance chemo-resistance | Gene and chemo-inhibitor | WB, IHC | (24, 25) |
| sPD-L1 | Serum | Integrity or splice variant | Secretion from cancer cells/matured APCs | Bind with PD-1, associated with immune state | Antibody, gene, and chemo-inhibitor | ELISA | (29) |
| Serum | Without transmembrane motifs | Enzyme cleavage | Bind with PD-1, associated with immune state | Antibody, gene, and chemo-inhibitor | ELISA | (19) | |
| – | – | Dimeric | Crystallization | Functional units or evolution relic | – | – | (30) |
*
The typical detection method: WB, Western blotting; IHC, Immunohistochemistry; ELISA, Enzyme-linked immunosorbent assay.