The upregulation of amino acid transporters in PSMA low/negative prostate carcinoma further suggests that PET imaging with radiolabeled amino acids, e.g., [18F]-Fluciclovine PET/CT may provide comparable information to that of FDG-PET and also explains why [18F]-Fluciclovine PET/CT imaging is less performing for detection of recurrent prostate carcinoma when compared to PSMA-targeted PET-imaging [55]. This evidence concerns the gene FOLH1 and prostate carcinoma.