CD274 and neoplasm: At the protein level, analysis of 100 TNBC clinical samples by mIF revealed no correlation (Spearman’s rank correlation coefficient = -0.07, p-value = 0.44; Pearson = 0.03, p-value = 0.75) between stromal PD-L1 and tumor-bound MerTK optical density (OD) (Figures 7E, F).