CD274 and neoplasm: Figure 6B shows quantitative expression of tumor, stromal and immune cells in the tissue array. While a Pearson correlation matrix (Figure 6C) of all proteins measured allowed us to identify a significant correlation between increased MDSCs and PD-L1 (Figure 6C,D), a significant inverse correlation was observed between CD8 and markers specific for the stroma (Figure 6C,E). Among the proteins that were significantly correlated with the stromal markers were Arg1 (Figure 6F–H), and S100B (Figure 6I–K).