Among 36 patients with negative results for PSMA PET/CT, FDG PET/CT detected cancer sites in six patients, with mean PSA values of 16.7 ng/ml, compared with mean PSA values of 0.8 ng/ml in the 30 patients negative for both PSMA PET/CT and FDG PET/CT [68]. Here, KLK3 is linked to cancer.