Fig. 2.

Triple-negative breast cancer with positive PD-L1 expression. A The histology of the invasive breast cancer. Note the prominent stromal inflammatory infiltrate with abundant tumor-infiltrating lymphocytes (TILs). H&E. ×200. For both PD-L1 assays, SP263 (B ×100, C ×200, D ×400) and SP142 (E ×200, F ×400) (Staining, courtesy of Prof. Wilko Weichert), PD-L1 IHC showed positivity of TILs (immune cell [IC] score >1%). B–D Using SP263, few tumor cells showed membranous PD-L1 staining. E, F In contrast, the SP142 assay did not. However, this phenomenon is known and might be due to the fact that the SP142 assay was established to detect immune cells with high sensitivity, but not epithelial/tumor cells.