TIMP1 and neoplasm: In all the PDAC‐PDX models, circulating mouse TIMP1, MMP7, and TSP2 levels were significantly higher than in healthy mice (P < 0.05) (Fig 4A) paralleling the tumor growth in the pancreas as shown by the significant correlation with tumor burden measured by MRI (TIMP1, r = 0.68; MMP7, r = 0.60 and TSP2, r = 0.82) (Fig 4B).