Figure 5 . (A) Comparison of the micro-PET/CT images of A375 and HMVII tumor-bearing mice after administration of89Zr-IP150 or 18F-FDG via tail vein injection (n = 3/group). (B), (C) ROI and tumor/muscle ratio analysis of the PET images. The values are presented as the SUVmax (n = 3). ***, p < 0.001; ****, p < 0.0001.
To expand the clinical relevance of this study,89Zr-IP150 was evaluated in a MUC18 (+) melanoma PDX model (Figure 6C). Significant uptake in the tumor was observed from 24 hours to 96 hours in the MIP and coronal images (Figure 6A). The maximum tumor uptake was reached at 24 hours, with an SUVmax of 2.77±0.16, while the concentration of radioactivity in the heart decreased dramatically from 2 to 24 hours (3.23±0.04 to 0.70±0.04) (Figure 6B). In addition, pathological staining of the PDX model revealed no specific expression of MUC18 in normal tissues, such as the heart, liver, spleen, lung, kidney, stomach, small intestine, large intestine, muscle and brain (Supplementary Figure 3).