Fig. 14: PD-L1 in breast cancer.
From: Novel uses of immunohistochemistry in breast pathology: interpretation and pitfalls
PD-L1 in triple negative breast carcinoma is assessed with the immune cell (IC) score, equating to the percentage tumor area occupied by PD-L1+ immune cells, using the Ventana PD-L1 (SP142) assay. A primary triple negative breast carcinoma with minimal inflammatory infiltrate (A) is PD-L1 negative due to a PD-L1 immune cell (IC) score of 0% (B); nonspecific, punctate cytoplasmic labeling is seen within the tumor cells. A primary triple negative breast carcinoma with prominent inflammatory infiltrate (C) is PD-L1 positive due to an IC score of 20–25% (D), which falls above the IC positivity threshold of ≥1%.
