FAP and neoplasm: Analysis of Cohort 1 revealed that stromal FAP expression (normalised to total stroma area) was highest in MRI‐visible tumours [mean = 0.029, interquartile range (IQR) = 0.020], followed by MRI‐invisible tumours (mean = 0.011, IQR = 0.010), and benign regions (mean = 0.006, IQR = 0.010) (Kruskal–Wallis test, p < 0.001; Figure 3A).