CD40 and neoplasm: Additionally, CD40 QIF scores were highly concordant between serial sections (R2 = 0.89), confirming reproducibility, and showing some correlation between expression in the tumor and stroma compartments (R2 = 0.36), indicating that tumors with more CD40 expression in the stroma are more likely to also express CD40 on the tumor surface (Supplementary Fig. 1B, C).