FAP and esophageal cancer: Because of the high expression of FAP in esophageal cancer, FAPI PET shows a high uptake rate (SUVmax > 12) and high TBR in esophageal cancer and its metastases, and lymph node metastases of esophageal cancer with a false-negative 18F-FDG test are strongly positive by FAPI test, which improves the detection rate of lymph node lesions (31).