As the distribution of 64Cu-DOTA-11-25 mAb in the pancreas or stomach was of very low level (Figure 7), MSLN-positive pancreatic cancer or gastric cancer could be visualized in high contrast by in vivo PET imaging with 64Cu-DOTA-11-25 mAb. The gene discussed is MSLN; the disease is familial pancreatic carcinoma.