In our in vivo studies, we used 89Zr-labeled anti-HER2 (trastuzumab), 89Zr-labeled anti-EGFR (panitumumab), or 89Zr-labeled anti-MET (onartuzumab) antibodies to monitor RTK protein levels in RCC PDXs after targeted therapy. Here, EGFR is linked to renal cell carcinoma.