The most important clinical finding was that in 3 of 4 patients (75%) with negative [68Ga]Ga-PSMA-11 PET/CT, prostate cancer lesions (local recurrence or lymph node metastases) were identified by [89Zr]Zr-PSMA-617 PET/CT. This evidence concerns the gene FOLH1 and Familial prostate cancer.