Categorisation of MBCs based on PD-L1 expression in tumour cells and low or high PD-1 expression in TILs
| Type | Tumour microenvironment (PD-L1/PD-1 TILs) | Number of cases (n=71) |
|---|---|---|
| 1 | PD-L1 positive, high PD-1* | 16 (23%) |
| 2 | PD-L1 negative, low PD-1* | 22 (31%) |
| 3 | PD-L1 positive, low PD-1* | 14 (20%) |
| 4 | PD-L1 negative, high PD-1* | 19 (26%) |
*PD-1 categorisation as high or low is done around the median of 22.5.
MBC, metaplastic breast carcinoma; PD-1, programmed cell death 1; PD-L1; programmed death-ligand 1; TIL, tumour infiltrating lymphocyte.