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. 2018 Jun;9(3):404–415. doi: 10.21037/jgo.2018.01.09

Figure 3.

Figure 3

Multispectral fluorescent IHC staining (200×) and image analysis using a panel of markers including CD68, PD-L1, CK20, and DAPI on pretreatment tumor specimens in a responder to PD-1 blockade (top row) and a nonresponder to PD-1 blockade (bottom row) identified that PD-L1 expression was observed primarily on non-tumor cells, specifically on CD68+ tumor-associated macrophages. Case (top row) from a MSI-H mCRC patient with response to pembrolizumab and (bottom row) from a MSI-H mCRC patient with no response to pembrolizumab. Multispectral fluorescent IHC stains: CD68 (purple), PD-L1 (green), DAPI (blue). IHC, immunohistochemistry; PD-1, programmed cell death 1; PD-L1, programmed death ligand 1; CK20, cytokeratin 20; DAPI, 4',6-diamidino-2-phenylindole; MSI-H, microsatellite instability-high; mCRC, metastatic colorectal cancer.