MMP14 and neoplasm: Posterior quantitative analysis of tumor/blood ratios of 89Zr-DFO-LEM2/15 compared with control 89Zr-DFO-IgG1 distribution (1.17±0.23 and 1.50±0.14 versus 0.71±0.10 and 0.82±0.01 at 2 and 4 days p.i., respectively) revealed significant differences over time (Fig 4B and S3A Fig), indicating an MT1-MMP-mediated specific tumor uptake in this model.