In this study, the PET imaging using the 89Zr-labeled anti-MSLN-scFv clone (H1a050) with high reactivity to MSLN-expressing cancer cells clearly displayed the MSLN-positive tumor derived from NCI-N87 cancer cells but not the MSLN-negative tumor derived from PANC-1 cells (Figure 4). This evidence concerns the gene MSLN and neoplasm.