In a series of 21 patients with post-RP PSA relapse (median PSA: 1.98 ng/ml), 11C-choline PET/CT improved the detection of lymph node metastases that were subsequently confirmed by histological assessment in 19 of the 21 patients (90%) (47). The gene discussed is KLK3; the disease is metastatic malignant neoplasm in the lymph nodes.